2004 grand with 4.0 diagnostic code p0300
04-22-2012, 11:52 PM
#1
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Model: Cherokee
2004 grand with 4.0 diagnostic code p0300
i have an 04 grand cherokee with a 4.0 that has a code p0300 , 2 weeks ago it left me stranded would not start (and got it home 3 hours away) took it to my mechanic and he replaced the crankshaft position sensor and all seems well. yesterday i was driving on the highway and i noticed the cel was flashing so i got home home and read the code on the dash and it is a p0300 with no other codes , it has 78000 miles on it and it is my baby any ideas what it could be . also it did not stumble or act funny it drove just fine plenty of power no smells , etc etc .
04-23-2012, 08:09 AM
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Year: 2004
Model: Grand Cherokee
Engine: 4.7L V8
Welcome to CF. It always sucks when your vehicle breaks down on you. I checked that code: http://www.wjjeeps.com/faultcodes.htm#0300
but I can't tell you what causes a random cylinder misfire, sorry.
Have you checked to see if the recalls have been performed on your WJ yet? http://www.wjjeeps.com/recall.htm#2004
One is about the CPS's harness cracking, and one is about reprogramming the PCM's on board diagnostic system. Can't say if it's related to your issue or not though.
but I can't tell you what causes a random cylinder misfire, sorry.
Have you checked to see if the recalls have been performed on your WJ yet? http://www.wjjeeps.com/recall.htm#2004
One is about the CPS's harness cracking, and one is about reprogramming the PCM's on board diagnostic system. Can't say if it's related to your issue or not though.
04-23-2012, 04:18 PM
#3
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Year: 2002
Model: Grand Cherokee
Engine: 4.0L
How many miles on the plugs? Are they correctly gapped? Also did your mechanic reset the PCM when he replaced the crank sensor? Try resetting the PCM. You may have also gotten a bad tank of gas.
04-25-2012, 09:43 AM
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Year: 2004
Model: Grand Cherokee
Engine: 4.0 V6
It came with NGK plugs from the factory. Switched to Autolite platinum, not impressed. Now using Champion double platinum. Gap is .035. I like changing them every 30K. It's so easy on a straight 6.
04-25-2012, 12:30 PM
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Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
That code is for a random misfire, I would replace the plugs and inspect the spark plug boots for any signs of carbom tracking or pinholes and replace if necessary. I'm pretty sure there is nothing wrong with the coil pack. 78k on the original plugs will tend to open the gap and will cause some issues. The gas we are forced to use today has fewer carbon atoms, the ignition system needs the carbon atoms to help transfer the spark from the center electrode of the spark plug to the ground electrode. If the gap is too large for the spark to jump and there is no help from the lack of carbon atoms in the fuel, you will get a misfire.
05-22-2012, 02:40 PM
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Update I changed the plugs @ a week ago the old ones where original and the gap was huge . Also replaced the coil pack all for about $100 . I reset the check engine light all about 2 weeks ago , the other day I was driving @70 mph and I noticed the check engine light was flashing a couple of different codes . When I stopped and checked the OBD codes and nothing was there . Any ideas would be appreciated
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05-22-2012, 03:14 PM
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Year: 2016
Model: Grand Cherokee (WK2)
Engine: 5.7l HEMI
I found this:
NUMBER: 09-003-03
GROUP: Engine
DATE: Aug. 01, 2003
This bulletin is supplied as technical information only and is not an authorization for repair. No part of this publication may be reproduced, stored in a retreival system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise, without written permission of DaimlerChrysler Corporation.
SUBJECT:
4.0L Multiple Cylinder Misfire
OVERVIEW:
This bulletin involves inspection of all engine exhaust valves and a decarbonizing
procedure if necessary.
MODELS:
1999 - 2004 (WJ) Grand Cherokee (All Markets)
2001 - 2004 (WG) Grand Cherokee (International Markets)
1999 - 2004 (TJ) Wrangler
1999 - 2001 (XJ) Cherokee
NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A
4.0L ENGINE (SALES CODE = ERH).
SYMPTOM/CONDITION:
The customer may experience an incident of engine misfire during certain vehicle
operating conditons. The misfire may occur when the vehicle is operated between
80 - 112 KPH (50 - 70 MPH) and under light loading conditions, e.g. slight uphill
road grades. This condition may occur at all ambient conditions, but is more
noticeable when ambient conditons are less than 0 C (32 F).
If the vehicle is equipped with On-Board Diagnostic (OBD), a MIL illumination may also
have occurred due to Diagnostic Trouble Code (DTC) P0300 - Mulitiple Cylinder Misfire.
Various single cylinder misfire DTC’s may also be present. If the frequency of misfire is
high the Powertrain Control Module (PCM) may place the engine in “Limp-In” mode.
The misfire condition may be caused by one or more engine exhaust valves that are
slow to close. Late closure of an exhaust valve may be the result of no valve rotation
and associated build up of carbon on the exhaust valve stem.
DIAGNOSIS:
1. This condition may occur when the engine is not allowed to run at engine RPM’s that
are greater than 3,200 RPM. At 3,200 RPM or higher the engine exhaust valves
will rotate if not impeded by high carbon deposits. Low engine RPM’s and high
carbon deposits are associated with short trip driving where the vehicle engine is
not allowed to fully warm to normal engine operating temperatures. Cold ambient
temperatures will increase engine warm-up time and add to the opportunity of
carbon deposit build-up on the stem of the engine exhaust valve.
09-003-03 -2-
2. Verify that an engine misfire condition is present. Use of the DRBIII® during a road
test, or a Co-Pilot data recording, may help to determine engine misfire and misfire
counts. If carbon deposit accumulation is severe, then a cylinder leak down test
may detect one or more cylinders leaking greater than 15%. Save any misfire DTC
Freeze Frame Data that was stored for later misfire correction verification.
3. Verify that the engine misfire condition is not caused by faulty engine
mechanical or electrical components.
4. If the engine mechanical and electrical systems are operating properly
perform the Repair Procedure.
PARTS REQUIRED:
Qty. Part No. Description
1 04318001AB Mopar Combustion Chamber Cleaner
EQUIPMENT REQUIRED:
MD-998772A Valve Spring Compressor and Removal Essential Tool
REPAIR PROCEDURE:
INSPECTION:
1. Raise vehicle hood.
2. Remove the engine valve cover and all six exhaust valve rocker arms (the intake rocker
arms are also removed during this step). Refer to the appropriate vehicle Service
Manual for detailed removal instructions. The valve cover gasket is reuseable. Keep
each pair of rocker arms matched to their respective valve and cylinder.
3. Inspect the end, or tip, of each exhaust valve stem where it makes
contact with the respective rocker arm.
4. Determine if each exhaust valve is rotating within its respective valve guide. An
exhaust valve that is rotating will have a “bulls eye” or circular wear pattern on the
face of the valve stem tip. If the exhaust valve is not rotating a straight mark-like
pattern will be present across the face of the valve stem tip.
5. If there are exhaust valves which are not rotating then proceed to the VALVE
ROTATION section of this Repair Procedure.
6. If all exhaust valves are rotating, then this bulletin does not apply and further
diagnosis is required. Install the engine rocker arms and valve cover. Refer to the
appropriate vehicle Service Manual for detailed installation instructions.
VALVE ROTATION:
1. If one or more engine exhaust valves are not rotating, perform the valve
rotation procedure to all six (6) exhaust valves.
NOTE: IT IS IMPORTANT THAT THE VALVE ROTATION SECTION OF THIS
REPAIR PROCEDURE BE PERFORMED.
2. Clean and mark the tip of each exhaust valve stem with a paint marker. The paint mark
will be used later to assist with determining if the exhaust valve has been rotated 90 .
-3- 09-003-03
3. Bring number one (#1) cylinder piston to top dead center using the mark on the
crankshaft front dampener/pulley. This step is important to prevent the possibility
of the exhaust valve from falling completely into the cylinder.
4. Install the essential service tool valve spring compressor, MD-998772A,
to the #1 cylinder exhaust valve spring.
NOTE: THE FOLLOWING VALVE ROTATION PROCEDURE WAS DEVELOPED WITH
THE USE OF VALVE SPRING COMPRESSOR TOOL MD-998772A. THE MD-998772A IS
AN ESSENTIAL SERVICE TOOL AND PART OF THE DEALERSHIP REQUIRED TOOLS.
THE MD-998772A COMPRESSOR ENGAGES THE ENTIRE PERIMETER OF THE
VALVE SPRING RETAINER, UNLIKE OTHER MAKE VALVE SPRING COMPRESSORS.
5. Compress the #1 cylinder exhaust valve spring enough to gain access so that
the exhaust valve can be rotated 90 . Rotate the exhaust valve 90 . Slowly
remove the compression on the exhaust valve spring. Verify that the valve keeper
is properly seated to the valve stem and valve spring retainer.
6. The 4.0L firing order is 1 - 5 - 3 - 6 - 2 - 4. Without rotating the engine
crankshaft repeat steps 3 through 5 to cylinder #6.
7. Rotate the engine crankshaft 120 and repeat steps 3 through 5 to cylinders #5 and #2.
8. Rotate the engine crankshaft another 120 and repeat steps 3 through
5 to cylinders #3 and #4.
9. Install all cylinder rocker arms (intake and exhausts) and retaining bridge. Make certain
that the push rods are properly seated to their respective rocker arm and lifter. Tighten
the respective cylinder bridge/rocker arm cap screws to 30 Nm (21 ft. lbs.) when each
cylinder piston is at top dead center (cylinder intake and exhaust valves are closed).
10. Install the engine cylinder head valve cover. Tighten the valve cover bolts to 10 Nm (85 in.
lbs.). Refer to the appropriate vehicle Service Manual for detailed assembly instructions.
DECARBONING COMBUSTION CHAMBER AND VALVES:
1. Start the vehicle engine and allow the engine to reach normal operating temperature.
2. Remove the air tube from the engine throttle body.
3. With the engine at idle, spray the entire contents of Mopar Combustion Chamber
Cleaner, p/n 04318001AB, directly into the throttle body. As the cleaner is being
ingested, allow the vehicle to “load up” with the cleaner to the point that the engine is
almost stalling out. Maintain this condition until all of the cleaner is used/ingested.
4. Stop the engine once the entire can of cleaner has been ingested.
5. Install the air tube to the throttle body.
6. With the hood closed and the vehicle parked inside the garage, allow the vehicle
engine to heat soak for two to three hours. This will ensure that the engine will
maintain its temperature and will allow proper solvent penetration.
7. After engine soak, start the engine and drive the vehicle until the engine is
has reached normal engine operating temperatures.
8. If the vehicle is equipped with an automatic transmission, place the gear
selector into “L” (low). If the vehicle is equipped with a manual transmission,
place the transmission into first gear.
9. In a safe vehicle operating location that will allow the vehicle to be driven safely and at
the posted speed limit, accelerate the vehicle until the engine reaches 4500 RPM.
10. Hold the engine speed at this RPM for 15 seconds.
09-003-03 -4-
11. Slow down and in a safe location pull to the side of the road. Allow
the engine to idle for five seconds.
12. Repeat steps 9 through 11 five more times.
13. With the vehicle at operating temperature and using any available Freeze
Frame data recorded when the misfire DTC occurred, verify that the
misfire condition has been corrected.
14. Erase any engine DTC’s once the misfire condition has been corrected.
NUMBER: 09-003-03
GROUP: Engine
DATE: Aug. 01, 2003
This bulletin is supplied as technical information only and is not an authorization for repair. No part of this publication may be reproduced, stored in a retreival system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise, without written permission of DaimlerChrysler Corporation.
SUBJECT:
4.0L Multiple Cylinder Misfire
OVERVIEW:
This bulletin involves inspection of all engine exhaust valves and a decarbonizing
procedure if necessary.
MODELS:
1999 - 2004 (WJ) Grand Cherokee (All Markets)
2001 - 2004 (WG) Grand Cherokee (International Markets)
1999 - 2004 (TJ) Wrangler
1999 - 2001 (XJ) Cherokee
NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A
4.0L ENGINE (SALES CODE = ERH).
SYMPTOM/CONDITION:
The customer may experience an incident of engine misfire during certain vehicle
operating conditons. The misfire may occur when the vehicle is operated between
80 - 112 KPH (50 - 70 MPH) and under light loading conditions, e.g. slight uphill
road grades. This condition may occur at all ambient conditions, but is more
noticeable when ambient conditons are less than 0 C (32 F).
If the vehicle is equipped with On-Board Diagnostic (OBD), a MIL illumination may also
have occurred due to Diagnostic Trouble Code (DTC) P0300 - Mulitiple Cylinder Misfire.
Various single cylinder misfire DTC’s may also be present. If the frequency of misfire is
high the Powertrain Control Module (PCM) may place the engine in “Limp-In” mode.
The misfire condition may be caused by one or more engine exhaust valves that are
slow to close. Late closure of an exhaust valve may be the result of no valve rotation
and associated build up of carbon on the exhaust valve stem.
DIAGNOSIS:
1. This condition may occur when the engine is not allowed to run at engine RPM’s that
are greater than 3,200 RPM. At 3,200 RPM or higher the engine exhaust valves
will rotate if not impeded by high carbon deposits. Low engine RPM’s and high
carbon deposits are associated with short trip driving where the vehicle engine is
not allowed to fully warm to normal engine operating temperatures. Cold ambient
temperatures will increase engine warm-up time and add to the opportunity of
carbon deposit build-up on the stem of the engine exhaust valve.
09-003-03 -2-
2. Verify that an engine misfire condition is present. Use of the DRBIII® during a road
test, or a Co-Pilot data recording, may help to determine engine misfire and misfire
counts. If carbon deposit accumulation is severe, then a cylinder leak down test
may detect one or more cylinders leaking greater than 15%. Save any misfire DTC
Freeze Frame Data that was stored for later misfire correction verification.
3. Verify that the engine misfire condition is not caused by faulty engine
mechanical or electrical components.
4. If the engine mechanical and electrical systems are operating properly
perform the Repair Procedure.
PARTS REQUIRED:
Qty. Part No. Description
1 04318001AB Mopar Combustion Chamber Cleaner
EQUIPMENT REQUIRED:
MD-998772A Valve Spring Compressor and Removal Essential Tool
REPAIR PROCEDURE:
INSPECTION:
1. Raise vehicle hood.
2. Remove the engine valve cover and all six exhaust valve rocker arms (the intake rocker
arms are also removed during this step). Refer to the appropriate vehicle Service
Manual for detailed removal instructions. The valve cover gasket is reuseable. Keep
each pair of rocker arms matched to their respective valve and cylinder.
3. Inspect the end, or tip, of each exhaust valve stem where it makes
contact with the respective rocker arm.
4. Determine if each exhaust valve is rotating within its respective valve guide. An
exhaust valve that is rotating will have a “bulls eye” or circular wear pattern on the
face of the valve stem tip. If the exhaust valve is not rotating a straight mark-like
pattern will be present across the face of the valve stem tip.
5. If there are exhaust valves which are not rotating then proceed to the VALVE
ROTATION section of this Repair Procedure.
6. If all exhaust valves are rotating, then this bulletin does not apply and further
diagnosis is required. Install the engine rocker arms and valve cover. Refer to the
appropriate vehicle Service Manual for detailed installation instructions.
VALVE ROTATION:
1. If one or more engine exhaust valves are not rotating, perform the valve
rotation procedure to all six (6) exhaust valves.
NOTE: IT IS IMPORTANT THAT THE VALVE ROTATION SECTION OF THIS
REPAIR PROCEDURE BE PERFORMED.
2. Clean and mark the tip of each exhaust valve stem with a paint marker. The paint mark
will be used later to assist with determining if the exhaust valve has been rotated 90 .
-3- 09-003-03
3. Bring number one (#1) cylinder piston to top dead center using the mark on the
crankshaft front dampener/pulley. This step is important to prevent the possibility
of the exhaust valve from falling completely into the cylinder.
4. Install the essential service tool valve spring compressor, MD-998772A,
to the #1 cylinder exhaust valve spring.
NOTE: THE FOLLOWING VALVE ROTATION PROCEDURE WAS DEVELOPED WITH
THE USE OF VALVE SPRING COMPRESSOR TOOL MD-998772A. THE MD-998772A IS
AN ESSENTIAL SERVICE TOOL AND PART OF THE DEALERSHIP REQUIRED TOOLS.
THE MD-998772A COMPRESSOR ENGAGES THE ENTIRE PERIMETER OF THE
VALVE SPRING RETAINER, UNLIKE OTHER MAKE VALVE SPRING COMPRESSORS.
5. Compress the #1 cylinder exhaust valve spring enough to gain access so that
the exhaust valve can be rotated 90 . Rotate the exhaust valve 90 . Slowly
remove the compression on the exhaust valve spring. Verify that the valve keeper
is properly seated to the valve stem and valve spring retainer.
6. The 4.0L firing order is 1 - 5 - 3 - 6 - 2 - 4. Without rotating the engine
crankshaft repeat steps 3 through 5 to cylinder #6.
7. Rotate the engine crankshaft 120 and repeat steps 3 through 5 to cylinders #5 and #2.
8. Rotate the engine crankshaft another 120 and repeat steps 3 through
5 to cylinders #3 and #4.
9. Install all cylinder rocker arms (intake and exhausts) and retaining bridge. Make certain
that the push rods are properly seated to their respective rocker arm and lifter. Tighten
the respective cylinder bridge/rocker arm cap screws to 30 Nm (21 ft. lbs.) when each
cylinder piston is at top dead center (cylinder intake and exhaust valves are closed).
10. Install the engine cylinder head valve cover. Tighten the valve cover bolts to 10 Nm (85 in.
lbs.). Refer to the appropriate vehicle Service Manual for detailed assembly instructions.
DECARBONING COMBUSTION CHAMBER AND VALVES:
1. Start the vehicle engine and allow the engine to reach normal operating temperature.
2. Remove the air tube from the engine throttle body.
3. With the engine at idle, spray the entire contents of Mopar Combustion Chamber
Cleaner, p/n 04318001AB, directly into the throttle body. As the cleaner is being
ingested, allow the vehicle to “load up” with the cleaner to the point that the engine is
almost stalling out. Maintain this condition until all of the cleaner is used/ingested.
4. Stop the engine once the entire can of cleaner has been ingested.
5. Install the air tube to the throttle body.
6. With the hood closed and the vehicle parked inside the garage, allow the vehicle
engine to heat soak for two to three hours. This will ensure that the engine will
maintain its temperature and will allow proper solvent penetration.
7. After engine soak, start the engine and drive the vehicle until the engine is
has reached normal engine operating temperatures.
8. If the vehicle is equipped with an automatic transmission, place the gear
selector into “L” (low). If the vehicle is equipped with a manual transmission,
place the transmission into first gear.
9. In a safe vehicle operating location that will allow the vehicle to be driven safely and at
the posted speed limit, accelerate the vehicle until the engine reaches 4500 RPM.
10. Hold the engine speed at this RPM for 15 seconds.
09-003-03 -4-
11. Slow down and in a safe location pull to the side of the road. Allow
the engine to idle for five seconds.
12. Repeat steps 9 through 11 five more times.
13. With the vehicle at operating temperature and using any available Freeze
Frame data recorded when the misfire DTC occurred, verify that the
misfire condition has been corrected.
14. Erase any engine DTC’s once the misfire condition has been corrected.
The following users liked this post:
Marwell_Grimes (08-24-2023)
05-24-2012, 12:16 PM
#12
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Model: Cherokee
New update now upon driving it it started stumbling when I accelerated and is giving the check engine light flash code of 15 ( flashes ).and the obd code is p0300/0302/0304/0305 could the crankcase position sensor be bad again or ????????? Any ideas
05-24-2012, 06:42 PM
#13
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Year: 2016
Model: Grand Cherokee (WK2)
Engine: 5.7l HEMI
Those are all codes for multiple miss fires. When you replaced the spark plugs which brand did you use? While I am no expert, I have heard that Autolite plugs often cause problems for the 4.0l Jeep engine.
05-24-2012, 06:44 PM
#14
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Year: 2016
Model: Grand Cherokee (WK2)
Engine: 5.7l HEMI
Read this from a previous post.
Problem Solved.
I removed the Autolite Platinums and replaced them with Champion plugs and the vehicle started right up.
So strange. I quadrupled checked and those are the right type plugs in the Autolite line for this vehicle, but who knows.
Thanks for the help guys!
I removed the Autolite Platinums and replaced them with Champion plugs and the vehicle started right up.
So strange. I quadrupled checked and those are the right type plugs in the Autolite line for this vehicle, but who knows.
Thanks for the help guys!
05-24-2012, 06:59 PM
#15
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Year: 2001
Model: Cherokee
Engine: 4.0
Sounds like a low fuel pressure issue based on history. Easy enough to check with a basic fuel pressure gauge.
Put the plugs specified on the emissions sticker in it. If it calls for NGK xxx-xxxx use NGK xxx-xxxx. Chrysler/Jeep did the research, the guy at Autozone didn't.
Put the plugs specified on the emissions sticker in it. If it calls for NGK xxx-xxxx use NGK xxx-xxxx. Chrysler/Jeep did the research, the guy at Autozone didn't.
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Marwell_Grimes (08-24-2023)