P2122

P2122-PPS 1 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. (K23) APPS NO. 1 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 (K23) APPS No. 1 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 (K23) APPS No. 1 signal circuit open.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. (F855) APPS NO. 1 5-VOLT SUPPLY OPEN





Measure the resistance of the (F855) APPS No. 1 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 (F855) APPS No. 1 5-volt supply open.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. (K23) APPS NO. 1 SIGNAL CIRCUIT SHORTED TO GROUND





Measure the resistance between the (K23) APPS No. 1 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 (K23) APPS No. 1 signal circuit shorted to ground.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. (K23) APPS NO. 1 SIGNAL CIRCUIT SHORTED TO OTHER CIRCUITS





Measure the resistance between the (K23) APPS No. 1 signal 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 5

No

- Repair the (K23) APPS No. 1 signal circuit shorted to other circuits.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (F855) APPS NO. 1 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND





Measure the resistance between the (F855) APPS No. 1 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 (F855) APPS No. 1 5-volt supply circuit shorted to ground.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. (F855) APPS NO. 1 5-VOLT SUPPLY CIRCUIT SHORTED TO OTHER CIRCUITS





Measure the resistance between the (F855) APPS No. 1 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 (F855) APPS No. 1 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 (K23) APPS No. 1 signal circuit at the sensor harness connector and the (F855) APPS No. 1 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 P2123 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

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

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