Test Description

WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

5: This step determines if high resistance is present in the HO2S 1 ignition 1 voltage circuit.
6: This step determines if high resistance is present in the HO2S 1 heater low control circuit.

DTC P0053

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics (LX9) Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	IMPORTANT: The HO2S 1 Heater parameter may toggle to 0.00 A momentarily. Start the engine. Allow the engine to idle at operating temperature. Refer to Scan Tool Data List . Observe the HO2S 1 Heater parameter with a scan tool. Is the amperage within the specified range?	0.31-1.43 A	Go to Step 3	Go to Step 4
3	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. 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. Did the DTC fail this ignition?	-	Go to Step 4	Go to Testing for Intermittent Conditions and Poor Connections
4	Test the fuse that powers the heated oxygen sensor (HO2S) 1 for an open. Refer to Circuit Testing . Is the fuse open?	-	Go to Step 8	Go to Step 5
5	IMPORTANT: Use a known good ground. DO NOT use the HO2S 1 or the HO2S 2 heater low control circuits or the HO2S 1 or the HO2S 2 low signal circuits. Turn OFF the ignition. Disconnect the HO2S 1 and the HO2S 2. Turn ON the ignition, with the engine OFF. Connect a test lamp between the HO2S 1 ignition 1 voltage circuit, on the engine harness side and a good ground. Measure the voltage in parallel with the test lamp between the HO2S 1 ignition 1 voltage circuit terminal on the engine harness side and a good ground with a DMM. Connect a test lamp between the HO2S 2 ignition 1 voltage circuit on the engine harness side and a good ground. Measure the voltage in parallel with the test lamp between the HO2S 2 ignition 1 voltage circuit terminal on the engine harness side and a good ground with a DMM. Is the difference between the system voltage and either measured voltage more than the specified voltage?	0.5 V	Go to Step 12	Go to Step 6
6	Turn OFF the ignition. Remove the test lamp from the previous step. Connect a test lamp between the ignition 1 voltage circuit and the heater low control circuit on the engine harness side of the HO2S 1. Start the engine. Measure the voltage in parallel with the test lamp between the HO2S 1 heater low control circuit terminal, on the engine harness side and a good ground with a DMM. Turn OFF the ignition. Remove the test lamp from the previous test. Connect a test lamp between the ignition 1 voltage circuit and the heater low control circuit on the engine side of the HO2S 2. Start the engine. Measure the voltage in parallel with the test lamp between the HO2S 2 heater low control circuit terminal on the engine harness side and a good ground. Is either measured voltage more than the specified value?	0.5 V	Go to Step 7	Go to Step 10
7	Test the HO2S 1 and the HO2S 2 heater low control circuits for an open or high resistance. Refer to Circuit Testing , Wiring Repairs and Heated Oxygen Sensor (HO2S) Wiring Repairs . Did you find and correct the condition?	-	Go to Step 15	Go to Step 11
8	Test the HO2S 1 and the HO2S 2 ignition 1 voltage circuits for a short to ground and replace the fuse. Refer to Circuit Testing , Wiring Repairs and Heated Oxygen Sensor (HO2S) Wiring Repairs . Did you find and correct the condition?	-	Go to Step 15	Go to Step 9
9	IMPORTANT: Perform the following test on any HO2S that is supplied voltage by the suspect circuit. Test the HO2S 1 and the HO2S 2 ignition 1 voltage circuits on the sensor side of the HO2S connectors for a short to ground. Refer to Circuit Testing .Is any sensor shorted to ground?	-	Go to Step 13	Go to Testing for Intermittent Conditions and Poor Connections
10	Test for an intermittent and for a poor connection at the HO2S 1 and the HO2S 2. Refer to Testing for Intermittent Conditions and Poor Connections , Connector Repairs and Heated Oxygen Sensor (HO2S) Wiring Repairs . Did you find and correct the condition?	-	Go to Step 15	Go to Step 13
11	Test for intermittent and poor connections at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	-	Go to Step 15	Go to Step 14
12	Repair the open or high resistance condition in the HO2S 1 or the HO2S 2 ignition 1 voltage circuit. Refer to Wiring Repairs and Heated Oxygen Sensor (HO2S) Wiring Repairs . Did you complete the repair?	-	Go to Step 15	-
13	NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices. Replace the HO2S 1 or the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 1 or Heated Oxygen Sensor Replacement - Position 2 .Did you complete the replacement?	-	Go to Step 15	-
14	Replace the PCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?	-	Go to Step 15	-
15	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. 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. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 16
16	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle	System OK