fault codes P1694 and P0443.... starting issues
 

Hi all,

I have a 2000 sport, 4L, auto with a superchips programmer with the 91 octane tune. I bought the programmer mainly to try and get rid of the "dieseling" knocking sounds and for codes.

I live in Costa Rica and good mechanics and parts are hard to come by as well as good gas I would imagine. I have returned the tune to "stock" but still have the issue.

I have been experiencing the following problems for a while but the check engine light only showed up yesterday. The codes are
1. P1694 no engine bus messages
2. P0443 evap purge 1 control circuit.

Symptoms:
Does not start easily, turns over fine, hesitates to start unless I floor the accellerater then it will start.
It does not stall once running however I have a POS alarm that has a carjack function where you have to push a button when the led light starts flashing or it will stop the engine. Recently it has cut off the engine quite a few time due to my inability to see the light flashing. Could this be a factor in the fault codes being triggered?
The instrument cluster is working fine. ( I saw some other posts with similar issues but they had a problem with the cluster too).
The tranny seems to shift okay however it did have trouble going up a steep incline with 5 people in it a while back. It might be normal but I would think a straight 6 should power through it.... not sure.

I hope I was thorough enough with my info and any help would be greatly appreciated!

You have multiple issues.

I am including information on both of your trouble codes. Along with that, you could have a problem with your "throttle position sensor". Having to press on the accelerator to start it is often a problem with the TPS. They are not particularly expensive, and are easy to replace. Now onto the codes.
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"DTC P1694 will set if no CCd bus messages are received from PCM for 20 seconds or invalid messages are received for 20 seconds.

Possible Causes
Failed Crank Position Sensor
CCD Bus (-) circuit open between PCM and TCM.
CCD Bus (+) circuit open between PCM and TCM.
Transmission CCD bus wiring damaged.
Faulty TCM.
Failed CPS Symptoms -
-Fuel gauge and voltage gauges may not work or display properly.
-You sometimes will have No Bus on the odometer after 30-60 seconds.
-NO spark at the spark plugs.
-Fuel pressure is OK at the fuel rail.
If the CPS is failed sometimes the OBDII code reader cannot make a connection to the computer or cannot read Check Engine Light/MIL codes because the CPS has failed.

Crank sensors can have intermittent "thermal failure". This means that the sensor fails when engine gets hot, but works again when it cools back down. CPS failure with the JEEP 4.0 L is common at 80,000 and up, and will often cause secondary Check Engine Light/MIL codes.

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P0443 (M)Evap Purge Solenoid Circuit. An open or shorted condition detected in the EVAP purge solenoid control circuit.

Check the wires and wire connector at the Leak Detection Pump on the firewall.

Below is a link to a very good thread on what you should look at first with this code.

http://www.jeepforum.com/forum/f11/p0443-code-1182649/

Thanks for your response!

I unplugged and replugged the Evap selenoid and checked the hoses and it seemed to not trigger the P0443 code again. The P1694 hasn't triggered again either but it still is hesitant to start if not stone cold.

It could possibly be a thermal intermittant problem because it has about 80K mileage and idles a lot in traffic jams in the Costa Rican heat.

The guages work with no problems and never had an issue with it. I checked to make sure the gas guy put the cap on properly too.

I unplugged and replugged the TPS but no change. The connectors don't seem to look corroded. I will see how much they want one for one here. I might have to wait for a "mule" to smuggle me one down in their suitcase!

It was indeed the throttle position sensor. All is good now!!

Thanks again for the response!