rowdy34

I have 2001 Cherokee 4.0 that keeps throwing code P0135 after replacing the 02 sensor in Bank 1 Sensor 1 with the Bosch 13100. I have verified the element is getting power and ground…and that the sensors resistivity is about 4.0 Ohms (meaning I am all good there I believe), I have checked the fuses and ASD and deem them fine also but the CEL keeps coming back on after about 15 miles or so.
My question is what's next...a new ECU? The jeep runs and idles perfect; I just can’t seem to shake this P0135 and CEL.
Thanks,

rowdy34

Maybe a better question is what do I try next if the sensor replaced continues to set off the CEL wit the same code? I have tried all the other tips provided on the site with regards to the P0135 and they have been helpful in making the jeep run and idle better but not stopped the code from coming back.

Thanks

Anony

Is that your only code?

I would first try to diagnose the DTC or DTCs if you have more than one.

Also make sure the correct fuses exist in the PDC and aren't blowing.

http://www.jeepforum.com/forum/f11/p...-back-1419646/

Basic tests for the o2 sensor and its wiring & connectors ... open circuits, poor grounds, intermittent crossed wires, chaffed wires, etc. Its probable after 15 mins of driving a condition occurs that sets the DTC. I would first try to duplicate the DTC with the (ign. On engine off) and (ign On - engine at idle).

** see wire inspection and other tests

P0135-1/1 O2 SENSOR HEATER FAILURE

When Monitored: With battery voltage greater than 9 volts, at a cold start, ECT less than 147°F, battery temperature sensor equal to or less than 27°F, and engine at idle for at least 12 seconds.

Set Condition: O2 sensor voltage greater than 3 volts for 30 to 90 seconds.

POSSIBLE CAUSES

O2 HEATER ELEMENT
O2 SENSOR HEATER GROUND CIRCUIT OPEN
O2 HEATER RELAY OUTPUT CIRCUIT OPEN
INTERMITTENT CONDITION
PCM

Testing (these tests are normally done with a DRB-III tool, but you should be able perform some if not all using a DMM and/or a scan tool)

Test 1 -------------------

Turn the ignition on.

(With the DRBIII), read DTC’s.

Is the Good Trip Counter for this DTC displayed and equal to zero?

Test 2 --------------------

Turn the ignition off.

NOTE: Wait a minimum of 8 minutes to allow the O2 Sensor to cool down
before continuing the test. Allow the O2 Sensor voltage to stabilize between
0.4 to 0.6 volts.

Turn the ignition on.

(With the DRBIII, actuate the O2 Heater Test.)
(With the DRBIII, monitor O2 Sensor voltage for at least 2 minutes.)

Does the voltage stay between 0.4 and 0.6 volt?

Test 3 -------------------

NOTE: Allow the O2 sensor to cool down to room temperature.

Turn the ignition off.

Disconnect the O2 Sensor harness connector.

Measure the resistance across the O2 Sensor Heater element component side.

Is the resistance between 4.0 and 7.0 ohms?

No ® Replace the O2 Sensor.

Test 4 ----------------------------------

Turn the ignition off.

Disconnect the O2 Sensor harness connector.

Measure the resistance of the O2 Sensor Heater ground circuit in the O2 Sensor harness connector.

Is the resistance below 5.0 ohms?

No ® Repair the O2 Sensor Heater ground circuit for an open.

Test 5 ---------------------------

Turn the ignition off.

Disconnect the O2 Sensor harness connector.

(With the DRBIII actuate the O2 Heater Test.)

Measure the voltage of the O2 Heater Relay Output circuit in the O2 Sensor harness connector.

Is the voltage above 11.0 volts?

No - Repair the O2 Heater Relay Output circuit for an open.

Other tests -------------------------

(some may require a scan tool with live readout and to be able to collect freeze frame data)

_ With the engine running at normal operating temperature, monitor parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set.

_ Review the Freeze Frame information. If possible, try to duplicate the
conditions under which the DTC was set.

_ Refer to any Technical Service Bulletins (TSB) that may apply.

** Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.

** Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.

rowdy34

Hi Anony and thanks for that for procedure breakdown, I have answered/commented on your suggestion in red below and will finish the remaining later tonight.

Let me give you a little more info on my XJ (truth told it’s my wife’s daily driver), it has 153K and runs and idles great (maybe slightly hard to re-start if the engine is pistol hot). In the past few months I have replaced these items: new fuel pump, new fuel filter, new fuel screen, new fuel pressure regulator, new battery, cleaned throttle body and IACV, new injector for Cylinder #3, cleaned all 5 other injectors, new coil pack, and plugs. Now, I didn’t mention this earlier, but I also have a cold air intake installed and wondered if it could be in play? Either way thanks for chiming in on this!



Is that your only code? Yes

I would first try to diagnose the DTC or DTCs if you have more than one.

Also make sure the correct fuses exist in the PDC and aren't blowing.

http://www.jeepforum.com/forum/f11/p0135-keeps-comming-back-1419646/ confirmed the fuses and relays are good

Basic tests for the o2 sensor and its wiring & connectors ... open circuits, poor grounds, intermittent crossed wires, chaffed wires, etc. Its probable after 15 mins of driving a condition occurs that sets the DTC. I would first try to duplicate the DTC with the (ign. On engine off) and (ign On - engine at idle).

** see wire inspection and other tests

P0135-1/1 O2 SENSOR HEATER FAILURE

When Monitored: With battery voltage greater than 9 volts, at a cold start, ECT less than 147°F, battery temperature sensor equal to or less than 27°F, and engine at idle for at least 12 seconds.

Set Condition: O2 sensor voltage greater than 3 volts for 30 to 90 seconds.

POSSIBLE CAUSES

O2 HEATER ELEMENT
O2 SENSOR HEATER GROUND CIRCUIT OPEN
O2 HEATER RELAY OUTPUT CIRCUIT OPEN
INTERMITTENT CONDITION
PCM

Testing (these tests are normally done with a DRB-III tool, but you should be able perform some if not all using a DMM and/or a scan tool)

Test 1 ------------------- Completed at AutoZone

Turn the ignition on.

(With the DRBIII), read DTC’s. P0135

Is the Good Trip Counter for this DTC displayed and equal to zero? Didn’t see this variable

Test 2 --------------------

Turn the ignition off.

NOTE: Wait a minimum of 8 minutes to allow the O2 Sensor to cool down
before continuing the test. Allow the O2 Sensor voltage to stabilize between
0.4 to 0.6 volts.

Turn the ignition on.

(With the DRBIII, actuate the O2 Heater Test.)
(With the DRBIII, monitor O2 Sensor voltage for at least 2 minutes.)

Does the voltage stay between 0.4 and 0.6 volt?

Test 3 ------------------- Completed

NOTE: Allow the O2 sensor to cool down to room temperature.

Turn the ignition off.

Disconnect the O2 Sensor harness connector.

Measure the resistance across the O2 Sensor Heater element component side. 4.1

Is the resistance between 4.0 and 7.0 ohms? Yes

No ® Replace the O2 Sensor.

Test 4 ----------------------------------

Turn the ignition off.

Disconnect the O2 Sensor harness connector.

Measure the resistance of the O2 Sensor Heater ground circuit in the O2 Sensor harness connector.

Is the resistance below 5.0 ohms?

No ® Repair the O2 Sensor Heater ground circuit for an open.

Test 5 ---------------------------

Turn the ignition off.

Disconnect the O2 Sensor harness connector.

(With the DRBIII actuate the O2 Heater Test.)

Measure the voltage of the O2 Heater Relay Output circuit in the O2 Sensor harness connector.

Is the voltage above 11.0 volts?

No - Repair the O2 Heater Relay Output circuit for an open.

Other tests -------------------------

(some may require a scan tool with live readout and to be able to collect freeze frame data)

_ With the engine running at normal operating temperature, monitor parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set.

_ Review the Freeze Frame information. If possible, try to duplicate the
conditions under which the DTC was set.

_ Refer to any Technical Service Bulletins (TSB) that may apply.

** Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.

** Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
Last edited by Anony; Yesterday at 11:00 PM.