P2127

P2127-PPS 2 VOLTAGE TOO LOW





For complete wiring diagrams refer to Diagrams/Electrical.


- When Monitored:

While the key is on and during engine operation.

- Set Condition:

The APPS circuit voltage at the ECM goes below 0.13 volt for more than 2 seconds.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. (K29) APPS NO. 2 SIGNAL CIRCUIT OPEN





Turn the ignition off.

Disconnect the ECM harness connectors.

Disconnect the APPS harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the (K29) APPS No. 2 signal circuit between the APPS sensor harness connector and the ECM harness connector.

Is the resistance less than 10 ohms?

Yes

- Go To 2

No

- Repair the (K29) APPS No. 2 signal circuit open.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. (F856) APPS NO. 2 5-VOLT SUPPLY OPEN





Measure the resistance of the (F856) APPS No. 2 5-volt supply circuit between the APPS sensor harness connector and the ECM harness connector.

Is the resistance less than 10 ohms?

Yes

- Go To 3

No

- Repair the (F856) APPS No. 2 5-volt supply open.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. (K29) APPS NO. 2 SIGNAL CIRCUIT SHORTED TO GROUND





Measure the resistance between the (K29) APPS No. 2 signal circuit at the sensor harness connector and battery negative.

Is the resistance greater than 100 k ohms?

Yes

- Go To 4

No

- Repair the (K29) APPS No. 2 signal circuit shorted to ground.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. (K29) APPS NO. 2 SIGNAL CIRCUIT SHORTED TO OTHER CIRCUITS





Measure the resistance between the (K29) APPS No. 2 signal circuit at the ECM harness connector and all other circuits in the ECM harness connectors.

Is the resistance greater than 100 k ohms?

Yes

- Go To 5

No

- Repair the (K29) APPS No. 2 signal circuit shorted to other circuits.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (F856) APPS NO. 2 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND





Measure the resistance between the (F856) APPS No. 2 5-volt supply circuit at the sensor harness connector and battery negative.

Is the resistance greater than 100 k ohms?

Yes

- Go To 6

No

- Repair the (F856) APPS No. 2 5-volt supply circuit shorted to ground.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. (F856) APPS NO. 2 5-VOLT SUPPLY CIRCUIT SHORTED TO OTHER CIRCUITS





Measure the resistance between the (F856) APPS No. 2 5-volt supply circuit at the sensor harness connector and all other circuits in the ECM harness connector.

Is the resistance greater than 100 k ohms?

Yes

- Go To 7

No

- Repair the (F856) APPS No. 2 5-volt supply circuit shorted to other circuits.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. ECM

Reconnect the ECM harness connectors.

Turn the ignition on.

While monitoring with the scan tool, connect a jumper wire between the (K29) APPS No. 2 signal circuit at the sensor harness connector and the (F856) APPS No. 2 5-volt supply circuit at the sensor harness connector.


NOTE: With the sensor disconnected it is normal to have a APPS 1 and APPS 2 low voltage DTC set.

Did DTC P2128 set?

Yes

- Go To 8

No

- Replace and program the ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

8. APPS

Reconnect the APPS harness connector.

Monitor the APPS 1 and APPS 2 voltage with the scan tool while depressing the throttle pedal.

Is the voltage transition shown on the scan tool smooth while depressing the throttle and is the voltage swing smooth?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Replace the APPS.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test