Conditions for Clearing the DTC

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

A current DTC Last Test Failed clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
Clear the DTC with a scan tool.

DTC P2128

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Engine Controls?	-	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	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. Does the DTC fail this ignition?	-	Go to Step 4	Go to Step 3
3	Select the DTC option on the scan tool. Lightly touch and move the related accelerator pedal position (APP) sensor wiring harnesses and connectors while monitoring the DTC information. Did this DTC fail this ignition during the above test?	-	Go to Step 10	Go to Intermittent Conditions
4	Disconnect the APP sensor harness connector. Turn ON the ignition, with the engine OFF. Measure voltage at the APP sensor 2 signal circuit with a DMM. Does the DMM indicate voltage within the specified range?	4.8-5.2 V	Go to Step 5	Go to Step 7
5	Probe the signal circuit of the APP sensor 2 with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 8	Go to Step 6
6	Connect a fused jumper between the APP sensor 3 signal circuit and the APP sensor 2 low reference circuit. Observe the APP sensor 3 voltage parameter with a scan tool. Does the scan tool indicate APP sensor 3 voltage at the specified value?	0 V	Go to Step 12	Go to Step 10
7	Turn OFF the ignition. Disconnect the engine control module (ECM) harness connector containing the APP sensor 2 signal circuit. Test the APP sensor 2 signal circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 16	Go to Step 8
8	Turn ON the ignition. Test the APP sensor 2 signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 16	Go to Step 9
9	Turn OFF the ignition. Disconnect the ECM harness connectors. Test the APP sensor 2, signal circuit for a short to all other APP circuits at the APP sensor harness connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 16	Go to Step 13
10	Disconnect the ECM harness connector containing the APP sensor 2 low reference circuit. Test the APP sensor 2 low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 16	Go to Step 13
11	Repair the intermittent condition as necessary. Refer to Connector Repairs and Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 16	-
12	Inspect for poor connections at the harness connector of the APP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition?	-	Go to Step 16	Go to Step 14
13	Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition?	-	Go to Step 16	Go to Step 15
14	Replace the APP sensor assembly. Refer to Accelerator Pedal Position (APP) Sensor Replacement . Did you complete the replacement?	-	Go to Step 16	-
15	Replace the ECM. Refer to Engine Control Module (ECM) Replacement . Did you complete the replacement?	-	Go to Step 16	-
16	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 17
17	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK