P0135

SYMPTOM
P0135-02 SENSOR 1/1 HEATER PERFORMANCE

WHEN MONITORED
Engine running and heater duty cycle greater than 0%. Battery voltage greater than 11.0 volts.

SET CONDITION
No sensor output is received when the PCM powers up the sensor heater. Two trip fault. Three good trips to turn off the MIL.

POSSIBLE CAUSES
- (K99) 02 1/1 HEATER CONTROL CIRCUIT OPEN
- (Z43) 02 1/1 HEATER GROUND CIRCUIT OPEN
- 02 SENSOR HEATER ELEMENT
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Scan Tool Testing and Procedures

DIAGNOSTIC TEST
1. 02 SENSOR HEATER OPERATION





Turn the ignition off.

Note: Wait a minimum of 8 minutes to allow the 02 Sensor to cool down before continuing the test. Allow the 02 Sensor voltage to stabilize between 4.6 and 5.0 volts.

Ignition on, engine not running.
With a scan tool, actuate the 02 Heater Test.
With the scan tool, monitor 1/1 02 Sensor voltage for at least 2 minutes.
Does the voltage stay above 4.5 volts?
Yes>> Go To 2
No>> Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5. Powertrain Verification Test - Ver 5

2. 02 SENSOR HEATER ELEMENT

Turn the ignition off.

Note: Allow the 02 sensor to cool down to room temperature. Disconnect the 02 Sensor harness connector.

Measure the resistance of the 02 Heater Element across the 1/1 02 Sensor connector between the 02 Heater Control terminal and the Heater ground terminal.

Note: 02 Heater Element resistance values should be measured at 70 °F (21.1 °C). The resistance value will vary with different temperature values.

Is the resistance of the 02 Sensor Heater Element between 2.0 and 30.0 ohms?
Yes>> Go To 3
No>> Replace the 02 Sensor. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.

3. (K99) 02 1/1 HEATER CONTROL CIRCUIT OPEN





Disconnect the PCM harness connectors.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool # 8815 to perform diagnosis.

Measure the resistance of the (K99) 02 1/1 Heater Control circuit from the 02 harness connector to the appropriate terminal of special tool # 8815.
Is the resistance below 0.5 of an ohm?
Yes>> Go To 4
No>> Repair the excessive resistance in the (K99) 02 1/1 Heater Control circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.

4. (Z43) 02 1/1 HEATER GROUND CIRCUIT OPEN





Measure the resistance between ground and the (Z43) 02 1/1Heater ground circuit in the 02 Sensor harness connector.
Is the resistance below 0.5 of an ohm?
Yes>> Go To 5
No>> Repair the excessive resistance in the (Z43) 02 1/1 Heater ground circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.

5. PCM

Note: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes>> Repair as necessary. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Replace and program the Powertrain Control Module per Service Information. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.