Diagnostic Instructions

DTC Descriptors

DTC P0030 : HO2S Heater Control Circuit Sensor 1

DTC P0031 : HO2S Heater Control Circuit Low Voltage Sensor 1

DTC P0032 : HO2S Heater Control Circuit High Voltage Sensor 1

DTC P0053 : HO2S Heater Resistance Sensor 1

DTC P0135 : HO2S Heater Performance Sensor 1

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Heater Voltage Supply	P0031, P0130	P0030, P0053, P0130, P0135	--
Heater Low Control	P0030, P0130	P0031, P0053, P0135	P0032
Reference Voltage (Signal)	P0131	P0130, P2243	P0132
Low Reference (Ground)	P0130, P0136	P0130, P2251	P0132
Pump Current	P0130, P0131, P2237	P2237	P0132, P2237
Trim Current	P0130, P0131, P2626	P2626	P0132, P2626

Circuit/System Description

Heating elements inside the heated oxygen sensor (HO2S) minimize the time required for the sensors to reach operating temperature and provide an accurate voltage signal. A low side driver within the engine control module (ECM) is pulse-width controlled to provide current to the heater elements. The ECM will not allow continuous HO2S heating until calibrated limits of time, temperature, and intake airflow have been reached. The ECM continuously monitors the HO2S heater current draw and operating state by briefly turning OFF the heater low side driver at regular intervals. A small reference voltage of approximately 4.9 volts is present at the heater low control circuit. When the low side driver is commanded ON the reference voltage is low. When the low side driver is commanded OFF the reference voltage is high, close to battery voltage. If the ECM detects that the predicted voltage and the detected voltage are different, a DTC sets.

Conditions for Running the DTC

P0030, P0031, P0032

P0053

P0135

Conditions for Setting the DTC

P0030, P0031, P0032

The ECM detects that the difference between the predicted voltage and the actual voltage exceeds a calibrated limit.

P0053

The ECM detects that the difference between the predicted resistance and the actual resistance of the HO2S 1 heater exceeds a calibrated limit.

P0135

Action Taken When the DTC Sets

DTC P0030, P0031, P0053, P0135 are Type B DTCs.

Conditions for Clearing the DTC

DTC P0030, P0031, P0053, P0135 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Clear the DTCs with a scan tool.
2. Operate the vehicle within the conditions for running and setting the DTC. The DTC should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the B52A HO2S 1.
2. Ignition ON, verify that a test lamp illuminates between the B52A HO2S 1 heater voltage supply circuit terminal 4 and ground.

⇒	If the test lamp does not illuminate, test the B52A HO2S 1 heater voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B52A HO2S 1 heater voltage supply circuit fuse is open, test all components connected to the fuse and replace as necessary.

3. Ignition ON, measure for approximately 4.9 volts between the B52A HO2S 1 heater low control circuit terminal 3 and ground.

⇒	If less than the specified value, test the B52A HO2S 1 heater low control circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.

⇒	If more than the specified value, test the B52A HO2S 1 heater low control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

4. Engine OFF, install a test lamp between the B52A HO2S 1 voltage supply circuit terminal 4 and the B52A HO2S 1 heater low control circuit terminal 3. Allow the K20 ECM to power down.
5. Engine RUNNING, the lamp should be ON steady.

⇒	If the test lamp is not on steady, replace the K20 ECM.

6. If the ECM and all circuits test normal, replace the B52A HO2S 1.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.