Diagnostic Test

ACTIVE DTC
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 .
O2 HEATER ELEMENT
1. Turn the ignition off.
  NOTE: Allow the O2 1/1 Sensor to cool down to room temperature.
2. Disconnect the O2 Sensor 1/1 harness connector.
3. Measure the resistance across the O2 Sensor 1/1 Heater element between the O2 1/1 Heater Control terminal and the O2 1/1 Heater ground terminal at the component.
  NOTE: O2 Heater Element resistance values should be measured at 21.1° C (70° F). The resistance value will vary with different temperature values.
  
  Is the O2 Sensor Heater Element resistance between 2.0 and 30.0 Ohms?
  
  Yes
  - Go to step 3
  No
  - Replace the O2 Sensor 1/1.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K99) O2 1/1 HEATER CONTROL CIRCUIT

Fig 1: Using 12 Volt Test Light Connected To Ground To Check O2 1/1 Heater Control circuit In Oxygen Sensor 1/1 Harness Connector
Courtesy of CHRYSLER LLC
1. Ignition on, engine not running.
  NOTE: Make sure the test light is probing the circuit before actuating the Heater Test or a DTC may set and not allow the actuation.
2. Using a 12-volt test light connected to ground, probe the (K99) O2 1/1 Heater Control circuit in the O2 Sensor 1/1 harness connector.
3. With a scan tool, actuate the O2 1/1 Heater Test with the O2 Sensor harness connector still disconnected.
  NOTE: The test light should be illuminated and bright proportional to the maximum duty cycle allowed by the scan tool. For example, if the scan tool allows 100% actuation, the brightness should be as bright as a direct connection to the battery. If the scan tool allows a maximum 25% actuation, the test light will flash dimly.
  
  Does the test light illuminate accordingly during the actuation?
  
  Yes
  - Go to step 4
  No
  - Go to step 5
O2 1/1 HEATER GROUND CIRCUIT OPEN

Fig 2: Measuring Resistance Between Engine Ground And O2 Sensor Heater Ground Circuit In O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Measure the resistance between an engine ground and the O2 1/1 Heater ground circuit in the O2 Sensor 1/1 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Replace the O2 Sensor 1/1.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Repair the open in the O2 1/1 Heater ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K99) O2 1/1 HEATER CONTROL CIRCUIT SHORTED TO VOLTAGE

Fig 3: Checking O2 1/1 Heater Control Circuit For Short To Voltage
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the C2 PCM harness connector.
3. Ignition on, engine not running.
4. Measure the voltage of the (K99) O2 1/1 Heater Control circuit in the 1/1 Oxygen Sensor harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (K99) O2 1/1 Heater Control circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 6
(K99) O2 1/1 HEATER CONTROL CIRCUIT OPEN

Fig 4: Measuring Resistance Of O2 1/1 Heater Control Circuit Between The Oxygen Sensor 1/1 Harness Connector & PCM Harness Connector
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the C2 PCM harness connector.
3. Measure the resistance of the (K99) O2 1/1 Heater Control circuit from the O2 Sensor 1/1 harness connector to the appropriate terminal of PCM harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go to step 7
  No
  - Repair the open in the (K99) O2 1/1 Heater Control circuit.
  - Perform the POWERTRAIN 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 Oxygen Sensor 1/1 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. Verify that there is good pin to terminal contact in the Sensor and Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Replace and program the Powertrain Control Module in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .