Diagnostic Test

1) DTC IS ACTIVE
Turn the ignition on.

With a scan tool, select View DTCs. Record DTC and Freeze Frame information.

Start the engine and allow it to idle for at least 60 seconds.

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 can result in personal injury or death.

With a scan tool, select View DTCs.

Is the status Active for this DTC?

Yes
1. Go to 2).
No
1. Refer to *CHECKING FOR AN INTERMITTENT DTC .
2) (K243) O2 2/2 SIGNAL CIRCUIT
Turn the ignition off.

Disconnect the 2/2 O2 Sensor harness connector.

Turn the ignition on.

With a scan tool, read the 2/2 O2 Sensor voltage.

Is the 2/2 O2 Sensor voltage above 4.8 volts?

Yes
1. Go to 3).
No
1. Go to 5).
3) 2/2 O2 SENSOR

Fig 1: Measuring The Voltage On The O2 Return (Up) Circuit In The 2/1 O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC

Measure the voltage on the (K904) O2 Return (Down) circuit in the 2/2 O2 Sensor harness connector.

Is the voltage at 2.5 volts?

Yes
1. Replace the 2/2 O2 Sensor.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 4).
4) (K904) O2 RETURN (DOWN) CIRCUIT SHORTED TO GROUND

Fig 2: Measuring The Resistance Between Ground And The O2 Return Circuit In The 1/1 O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC

Turn the ignition off.

Disconnect the Powertrain Control Module (PCM) harness connector.

Measure the resistance between ground and the (K904) O2 Return (Down) circuit in the 2/2 O2 Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the (K904) O2 Return (Down) circuit for a short to ground.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 7).
5) (K243) O2 2/2 SIGNAL CIRCUIT SHORTED TO GROUND

Fig 3: Measuring The Resistance Between Ground And The (K41) O2 1/1 Signal Circuit In The 1/1 O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC

Measure the resistance between ground and the (K243) O2 2/2 Signal circuit in the 2/2 O2 Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the (K243) O2 2/2 Signal circuit for a short to ground.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 6).
6) (K243) O2 2/2 SIGNAL CIRCUIT SHORTED TO THE (K904) O2 RETURN (DOWN) CIRCUIT

Fig 4: Measuring The Resistance Between The O2 1/1 Signal Circuit And The O2 Return (Up) Circuit In The 1/1 O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC

Measure the resistance between the (K243) O2 2/2 Signal circuit and the (K904) O2 Return (Down) circuit in the 2/2 O2 Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short between the (K243) O2 2/2 Signal circuit and the (K904) O2 Return (Down) circuit.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 7).
7) POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 2/2 O2 Sensor and the Powertrain Control Module (PCM).

Look for any chafed, pierced, pinched, or partially broken wires.

Look for broken, bent, pushed out or corroded terminals.

Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes
1. Repair as necessary.
2. Perform PCM VERIFICATION TEST .
No
1. Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
2. Perform PCM VERIFICATION TEST .