Diagnostic Test

DTC IS ACTIVE
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 possible serious or fatal injury.

NOTE: If P0688-AUTO SHUTDOWN RELAY SENSE CIRCUIT LOW has set along with any of the O2 SENSOR HEATER CIRCUIT HIGH DTCs, all of the O2 Sensor Heater Control circuits need to be checked for a short to battery voltage.
1. Start the engine and allow it to idle for at least 60 seconds.
2. With a scan tool, select View DTCs.
  Is the DTC Active at this time?
  
  Yes
  - Go to step 2
  No
  - Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
1/2 OXYGEN SENSOR

Fig 1: Measuring Resistance Of O2 Sensor Heater Element Across Oxygen Sensor Connector Between Heater Control Terminal And Ground Terminal
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
  NOTE: Allow the sensor to cool to ambient temperature before continuing. The voltage should stabilize between 4.6 and 5.0 volts.
2. Disconnect the 1/2 Oxygen Sensor harness connector.
3. Measure the resistance of the O2 sensor heater element across the 1/2 Oxygen Sensor connector between the heater control terminal and the ground terminal.
  NOTE: The resistance of the heater element will vary according to temperature and should be measured at 70° F (21.1° C).
  
  Is the resistance between 2.0 and 30.0 Ohms?
  
  Yes
  - Go to step 3
  No
  - Replace the 1/2 Oxygen Sensor in accordance with the Service Information.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K299) O2 1/2 HEATER CONTROL CIRCUIT SHORTED TO VOLTAGE

Fig 2: Measuring Voltage Of O2 Sensor Heater Control Circuit In Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Powertrain Control Module (PCM) harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (K299) O2 1/2 Heater Control circuit in the 1/2 Oxygen Sensor harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (K299) O2 1/2 Heater Control circuit.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 4
(K299) O2 1/2 HEATER CONTROL CIRCUIT OPEN

Fig 3: Measuring Resistance Of O2 Sensor Heater Control Circuit Between Oxygen Sensor Harness Connector And Appropriate Terminal Of PCM Pinout Box 8815
Courtesy of CHRYSLER LLC
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 PCM Pinout Box 8815 to perform diagnosis.
2. Measure the resistance of the (K299) O2 1/2 Heater Control circuit between the 1/2 Oxygen Sensor harness connector and the appropriate terminal of PCM Pinout Box 8815.
  Is the resistance below 0.5 of an Ohm?
  
  Yes
  - Go to step 5
  No
  - Repair the open in the (K299) O2 1/2 Heater Control circuit.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
EXCESSIVE RESISTANCE IN THE (Z931) GROUND CIRCUIT

Fig 4: Using 12-Volt Test Light Connected To 12 Volts To Check Ground Circuit In Oxygen Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Using a 12-volt test light connected to 12 volts, check the (Z931) Ground circuit in the 1/2 Oxygen Sensor harness connector.
  NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
  
  Is the test light illuminated and bright?
  
  Yes
  - Go to step 6
  No
  - Repair the excessive resistance in the (Z931) Ground circuit.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 1/2 Oxygen Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Verify that there is good pin to terminal contact in the 1/2 O2 Sensor and Powertrain Control Module connectors.
5. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .