2014 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P1622-O2 SENSOR REFERENCE VOLTAGE CIRCUIT HIGH

Special Tools: Click to display a list of tools used in this procedure

For a complete wiring diagram, refer to the Wiring Information.


Possible Causes

O2 SENSOR RETURN CIRCUIT SHORTED TO VOLTAGE
O2 SENSOR RETURN CIRCUIT OPEN OR HIGH RESISTANCE
OXYGEN SENSOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Diagnostic Test


1. ACTIVE DTC

1. Ignition on, engine not running.
2. With the scan tool, select View DTCs. Copy DTC and Freeze Frame information.
3. Start the engine.

WARNING:

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

4. Allow the engine to reach normal operating temperature.
5. Monitor the scan tool for at least two minutes.
6. With the scan tool, select View DTCs.


Is the status Active for this DTC?

Yes


No


2. CHECK THE (K902) O2 SENSOR RETURN CIRCUIT FOR A SHORT TO VOLTAGE

1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Disconnect the O2 Sensor 1/1 harness connector.
4. Disconnect the O2 Sensor 2/1 harness connector.
5. Turn the ignition on.
6. Measure the voltage of the (K902) O2 Sensor Return circuit reference voltage circuit at the O2 Sensor 1/1 or 2/1 harness connector.


Is the voltage above 2.7 volts?

Yes


No


3. CHECK THE (K902) O2 SENSOR RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE

1. Turn the ignition off.

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 the GPEC Diagnostic Adaptor to perform the diagnosis.

2. Connect the Adapter, GPEC Diagnostic 10436 .
3. Measure the resistance of the (K902) O2 Sensor Return circuit between the O2 Sensor 1/1 and 2/1 harness connector and the GPEC Adaptor.


Is the resistance below 5.0 Ohms?

Yes


No


4. O2 SENSOR

1. Reconnect the PCM C2 harness connector.
2. Ignition on, engine not running.
3. With the scan tool, monitor the O2 Sensor 1/1 and 2/1 voltage.
4. Connect a jumper between the (K41) O2 Sensor 1/1 Signal circuit and the (K902) O2 Sensor Return circuit at the O2 Sensor 1/1 harness connector.
5. Connect a jumper between the (K43) O2 Sensor 2/1 Signal circuit and the (K902) O2 Sensor Return circuit at the O2 Sensor 2/1 harness connector.


Does the voltage read between 2.3 and 2.7 volts with the jumper installed?

Yes


No


5. POWERTRAIN CONTROL MODULE

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensors and the PCM.
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.


Were any problems found?

Yes


No