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| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ignition Voltage | P0030 00 | P0030 00 | - | P0131 5A, P0131 12 |
HO2S Heater Control Sensor 1 | P0031 00 | P0030 00 | P0032 00 | P064D 00 |
The Heated Oxygen Sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the sensor heater. The engine control module (ECM) controls the heater operation by first modulating the control circuit to ground when the sensors are cold. This prevents the possibility of thermal shock to the sensor, from condensation build up on the sensor, by controlling the sensors rate of heating. After a predetermined amount of time, the ECM commands the heaters ON continuously. Once the sensor reaches operating temperature, the ECM may modulate the heater control circuit to ground, to maintain a desired temperature.
The ECM controls the heater by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled up to voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.
| • | The ignition voltage is between 10-18 V. |
| • | The engine speed is greater than 80 RPM. |
| • | The HO2S heater is commanded ON and OFF at least once during the ignition cycle. |
| • | The DTCs run continuously once the above conditions are met for 2 s. |
The ECM detects an internal fault or an over temperature when the heater is commanded ON.
DTC P064D is a Type A DTC.
DTC P064D is a Type A DTC.
| • | If the condition is intermittent, move the harnesses and connectors, with the engine operating, while monitoring the scan tool Circuit Status parameters for the component. The Circuit Status parameters change from OK or Not Run to Fault if there is a condition with the circuit or a connection. |
| • | An open fuse in the HO2S heater circuit may be caused by the heater element. The condition may not be present until the sensor operates for a period of time. If no fault is present in the heater circuit, monitor the amperage of the heater using the DMM to determine if the heater element is the cause of the open fuse. Inspect the sensor pigtail or the harness for contacting the exhaust system. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Note: The ignition circuit supplies voltage to other components. Make sure you test all circuits for a short to ground or test all components for being shorted that share the ignition circuit.
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary. |
| ⇒ | If the voltage is less than the specified value, test the low reference circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the K20 Engine Control Module. |
| ⇒ | If the voltage is greater than the specified value, test the low reference circuit for a short to voltage. If the circuit test normal, replace the K20 Engine Control Module. |
| ⇒ | If less than the specified range, test the reference voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If greater than the specified range, test the reference voltage circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If less than the specified range, test the low reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
If less than the specified value, repair as necessary.
| ⇒ | If not within the specified range, replace the B52 Heated Oxygen Sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
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