Diagnostic Test
- OXYGEN SENSOR 1/1 HEATER CONTROL OPERATION
- Turn the ignition off.NOTE: Wait a minimum of eighty minutes to allow the sensor to cool down before continuing. The sensor voltage should stabilize between 2.47 and 2.52 volts.
- Turn the ignition on.
- With a scan tool, actuate the Oxygen Sensor 1/1 heater control.
- With the scan tool, monitor 1/1 O2 Sensor Volts for at least two minutes.
Does the voltage stay between 2.47 and 2.52 volts?
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 .
- Turn the ignition off.
- OXYGEN SENSOR 1/1
- Turn the ignition off.NOTE: Wait a minimum of eight minutes to allow the sensor to cool down before continuing.
- Disconnect the Oxygen Sensor 1/1 harness connector.
- Measure the resistance of the O2 sensor heater element across the Oxygen Sensor 1/1 connector between the heater control terminal and the ground terminal.NOTE: The O2 heater element resistance should be measured at 70°F (21.1°C). The resistance value will vary at different temperatures.
Is the resistance between 2.0 and 30.0 Ohms?
Yes
- Go to step 3
No
- Replace the Oxygen Sensor 1/1 in accordance with the Service Information.
- Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
- Turn the ignition off.
- (K99) O2 1/1 HEATER CONTROL CIRCUIT OPEN OR HIGH RESISTANCE
- Disconnect the Powertrain Control Module (PCM) harness connector.NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.
- Measure the resistance of the (K99) O2 1/1 Heater Control circuit from the Oxygen Sensor 1/1 harness connector to the Powertrain Control Module (PCM) harness connector.
Is the resistance below 0.5 of an Ohm?
Yes
- Go to step 4
No
- Repair the (K99) O2 1/1 Heater Control circuit for an open circuit or high resistance.
- Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
- Disconnect the Powertrain Control Module (PCM) harness connector.
- (Z931) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
- Using a 12-volt test light connected to 12 volts, check the (Z931) Ground circuit in the Oxygen Sensor 1/1 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 5
No
- Repair the (Z931) Ground circuit for an open circuit or high resistance.
- Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
- Using a 12-volt test light connected to 12 volts, check the (Z931) Ground circuit in the Oxygen Sensor 1/1 harness connector.
- POWERTRAIN CONTROL MODULE (PCM)
- 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).
- Look for any chafed, pierced, pinched, or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals.
- 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 .