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Home >> Cadillac >> 2004 >> CTS Base, 3.6 7 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 15 (Engine Controls - 2.6L & 3.2L - Diagnosis (DTC P2096 - P2636)) >> Diagnostic Trouble Codes >> DTC P2127 >> Conditions for Clearing the MIL/DTC

Conditions for Clearing the MIL/DTC

WARNING: This page is about a different variant/trim than selected.
DTC P2127

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
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the accelerator pedal position (APP) sensor 2 voltage with a scan tool.
Is the APP sensor 2 voltage less than the specified value?
0.6 V Go to Step 5  Go to Step 3 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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 5  Go to Step 4 
4
  1. Clear the DTCs with a scan tool.
  2. Slowly depress the accelerator pedal to wide open throttle (WOT), then slowly return the accelerator pedal to the rest position.
  3. Repeat this action several times.
Did the DTC fail this ignition?
- Go to Step 18  Go to Intermittent Conditions
5
  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal position (APP) sensor harness connector. Refer to Accelerator Pedal Position (APP) Sensor Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the 5-volt reference circuit of the APP sensor 2 to a good ground with a DMM.
Is the voltage within the specified range?
4.8-5.2 V Go to Step 6  Go to Step 10 
6
  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the APP sensor 2 and the signal circuit of the APP sensor 2.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the APP sensor 2 voltage with a scan tool.
Is the APP sensor 2 voltage within the specified value?
4.8-5.2 V Go to Step 7  Go to Step 12 
7
  1. Turn OFF the ignition for 30 seconds.
  2. IMPORTANT: It may be necessary to remove the ECM/TCM fuse to allow the ECM to power down.
  3. Allow the engine control module (ECM) to completely power down. This can be verified by the loss of communication on the scan tool.
  4. Measure the resistance from the low reference circuit of the APP sensor 2 to a good ground with a DMM.
Is the resistance less than the specified value?
5 ohm Go to Step 15  Go to Step 8 
8 Test the low reference circuit of the APP sensor 2 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 20  Go to Step 9 
9 Measure the resistance from the case of the ECM to the battery ground.
Is the resistance less than the specified value?
5 ohm Go to Step 16  Go to Step 14 
10
  1. Disconnect all components that share the 5-volt reference voltage source one at a time.
  2. Measure the voltage from the 5-volt reference circuit of the APP sensor 2 to a good ground with a DMM.
Is the voltage within the specified range after disconnecting each component?
4.8-5.2 V Go to Step 17  Go to Step 11 
11 Test the 5-volt reference circuit of the APP sensors for the following conditions:
  • A short to ground
  • High resistance
  • An open circuit

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 20  Go to Step 13 
12 Test the signal circuit of the APP sensor 2 for the following conditions:
  • A short to ground
  • A short to the low reference circuit
  • High resistance
  • An open circuit

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 20  Go to Step 16 
13 Test the 5-volt reference circuit of the throttle position (TP) sensors for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 20  Go to Step 16 
14 Repair the open or high resistance in the ECM ground circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?
- Go to Step 20  -
15 Test for an intermittent and for a poor connection at the APP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 20  Go to Step 18 
16 Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 20  Go to Step 19 
17 Replace the component that, when disconnected, caused the voltage to return to the specified value in step 10. Refer to the appropriate replacement procedure.
Did you complete the replacement?
- Go to Step 20  -
18 Replace the accelerator pedal assembly. Refer to Accelerator Pedal Position (APP) Sensor Replacement .
Did you complete the replacement?
- Go to Step 20  -
19 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?
- Go to Step 20  -
20
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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 21 
21 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