Test Description
WARNING: This page is about a different car, the 2004 Chevrolet Corvette. 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.
- 2: TP sensor 2 and the APP sensor 2 share a common 5-volt reference source. Diagnose DTC P0220 first, if this DTC is also set.
- 18: This test determines whether the TAC module can recognize a change in signal voltage.
- 19: There are 3 separate 5-volt reference sources within the TAC module. TP sensor 1 and APP sensor 1 share one 5-volt reference source, TP sensor 2 and APP sensor 2 share another common 5-volt reference source and APP sensor 3 uses the third by itself. This test determines whether the signal circuit is shorted to any one of the 5-volt reference circuits. If a short exists, the corresponding sensor voltage will be pulled low.
- 20: The previous step found the signal circuit and a 5-volt reference circuit shorted together. This test isolates whether the short is in the harness or within the TAC module.
- 26: When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the Capture Info.
DTC P2125
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics 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-Engine Controls? | - | Go to Step 2 | Go to Diagnostic System Check - Engine Controls |
| 2 |
IMPORTANT:
If DTC P1518 or P0220 is also set, refer to Diagnostic Trouble Code (DTC) List
and diagnose the applicable DTC first.
|
3.90-4.81 V | Go to Step 3 | Go to Step 6 |
| 3 | Fully depress the accelerator pedal to the wide open throttle (WOT) position. Does the scan tool indicate APP sensor 2 voltage is within the specified values? |
0.83-2.9 V | Go to Step 4 | Go to Step 6 |
| 4 |
|
- | Go to Step 25 | Go to Step 5 |
| 5 | Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle while observing the DTC status. Did the scan tool indicator this DTC failed this ignition during the above test? |
- | Go to Step 21 | Go to Diagnostic Aids |
| 6 |
|
3.94-6.06 V | Go to Step 11 | Go to Step 7 |
| 7 |
|
- | Go to Step 25 | Go to Step 8 |
| 8 | Test the APP sensor 2 signal circuit for an open or for high resistance, with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 25 | Go to Step 9 |
| 9 | Test the APP sensor 2 signal circuit for a short to ground, with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 25 | Go to Step 10 |
| 10 | Test for a short between the APP sensor 2 signal circuit and all other TAC module circuits, with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 25 | Go to Step 23 |
| 11 | Test the APP sensor 2 5-volt reference circuit for voltage, with a DMM. Does the DMM indicate voltage within the specified values? |
3.94-6.06 V | Go to Step 16 | Go to Step 12 |
| 12 |
|
- | Go to Step 25 | Go to Step 13 |
| 13 | Test the APP sensor 2 5-volt reference circuit for an open or high resistance, with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 25 | Go to Step 14 |
| 14 | Test the APP sensor 2 5-volt reference circuit for a short to ground, with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 25 | Go to Step 15 |
| 15 | Test for a short between the APP sensor 2 5-volt reference circuit and all other TAC module circuits, with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 25 | Go to Step 23 |
| 16 | With a DMM connected between the APP sensor 2 low reference circuit and the APP sensor 1 low reference circuit, measure resistance. Does the DMM indicate resistance within the specified values? |
0-5 ohm | Go to Step 18 | Go to Step 17 |
| 17 |
|
- | Go to Step 25 | Go to Step 23 |
| 18 |
|
0 V | Go to Step 19 | Go to Step 23 |
| 19 |
|
- | Go to Step 20 | Go to Step 21 |
| 20 |
|
- | Go to Step 25 | Go to Step 23 |
| 21 | 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 25 | Go to Step 22 |
| 22 | Replace the APP sensor assembly. Refer to Accelerator Pedal Position (APP) Sensor Replacement
. Did you complete the replacement? |
- | Go to Step 25 | - |
| 23 | Inspect for poor connections at the harness connector of the TAC module. 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 25 | Go to Step 24 |
| 24 | Replace the TAC module. Refer to Throttle Actuator Control (TAC) Module Replacement
. Did you complete the replacement? |
- | Go to Step 25 | - |
| 25 |
|
- | Go to Step 26 | Go to Step 2 |
| 26 | 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 |