code P0135

2001 DODGE CARAVAN
140,000 MILES • 3.3L • 6 CYL • 2WD • AUTOMATIC
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DMITRY122
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Already three sensors are replaced in the van after a run of 500-1,000 miles each. Error code P0135 appears.
When checking the sensor heater, the ohmmeter shows an open cirсuit!
The sensors are Mopar 04686938AB and Denso.
Please help me to understand the problem.

Usually the "CE" was lit at the gas station, after turning off the engine for five minutes.
Apr 25, 2018 at 5:41 AM
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ASEMASTER6371
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Good morning.

The 135 code is for the Bank 1 or upstream O2 sensor heater circuit. the code tells you the area of failure not the part failure.

I listed below a description and possible cause for the code. It could be wiring issue, harness damage connector damage or a failing PCM.

you would need a advanced scan tool to monitor the heater operation of the sensor to determine if the heater is falling out.

check the harness for the sensor and be sure it is not laying on anything hot causing melting or damaging wires.

Roy

SYMPTOM
P0135-1/1 02 SENSOR HEATER FAILURE

WHEN MONITORED
During vehicle shutdown after vehicle had been driven greater than ten miles with throttle open for a minimum of three minutes. Battery voltage greater than 11.0 volts.

SET CONDITION
O2 sensor voltage continues to rise (instead of fall) after the diagnostics has turned the ASD relay back ON. Two trip fault.

POSSIBLE CAUSES
- O2 heater element.
- O2 sensor heater control circuit open.
- O2 sensor heater control circuit shorted to ground.
- ASD relay output circuit open.
- Intermittent condition.
- PCM.
Apr 25, 2018 at 5:51 AM
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DMITRY122
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Hello,
Thank you for answer.
I wonder why the heater burns out in all sensors.
I will test by the lamp applying voltage to the heater.
Should it be turned off when the engine warms up?
Is heater controlled by PWM from PCM?
Apr 25, 2018 at 6:22 AM
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ASEMASTER6371
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Not saying the heater is burned out at all. check the resistance of the heater portion from all the ones you had to a new one. my bet is they are all the same.

yes, it is pulse width modulated by the PCM.

no, it stays on while the engine is running. it needs to keep the sensor hot so the signal is accurate going to the PCM.

Roy
Apr 25, 2018 at 6:26 AM
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DMITRY122
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I checked the heater resistance before sensor installation.
The new sensor has a heater resistance 2.6 ohms.
Apr 25, 2018 at 6:30 AM
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STRAILER
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Yes, the old sensor sounds bad. here is a guide to help you get the sensor replaced:

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Since they keep burning out it sounds like you have a bad ground for that sensor which will cause high resistance across the sensor.

Here is a guide to help you run the test to confirm the issue:

https://www.2carpros.com/articles/how-to-check-wiring


Check out the diagrams (below).

Let us know what happens and please upload pictures or videos of the problem.

Cheers, Ken
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Apr 27, 2018 at 10:39 AM