Test Step 7. Disconnect the Power Supply Connections for the Accelerator Pedal Position Sensor at the ECM

148

TM 9-2320-312-24-2

Troubleshooting Section

Result 2 If the engine responds with the "Power

If the battery voltage is correct, temporarily

connect a test ECM. Use ET to verify that the

Train Data Link" in a disabled condition and

active diagnostic code is resolved. If the problem

the engine does not respond with the "Power

is corrected with the test ECM, reconnect the

Train Data Link" in an enabled condition, a

suspect ECM. Verify that the active diagnostic

component of the "Power Train Data Link" is

code returns. If the active diagnostic code returns

causing the response problem of the accelerator

with the suspect ECM, replace the ECM.

pedal position sensor. Send the truck to the

vehicle manufacturer in order to repair the faulty

component of the "Power Train Data Link". STOP.

STOP.

Result 3 The ECM is operating in PTO mode.

Not OK

Repair: If the PTO should not be active, refer to the

Repair: Perform the following repair:

following diagnostic procedure:Troubleshooting,

"PTO Switch Circuit - Test"

There is a problem in the wiring between the ECM

and the accelerator pedal position sensor. While

active diagnostic codes are being monitored,

STOP.

connect the removed wires one at a time in

Test Step 7. Disconnect the Power Supply

order to verify that the active diagnostic codes

Connections for the Accelerator Pedal

reappear. First connect P1:5 and then connect

Position Sensor at the ECM

P1:4. This procedure is used to find the wire

that is causing the problem. Repair the wire or

replace the wire, as required. Verify that the repair

A. Turn the ignition key switch to the OFF position.

eliminates the problem.

B. Remove P1:4 (+8 V) and remove P1:5

STOP.

(Accelerator/Switch Sensor Common) from

vehicle harness connector P1. Disconnect ECM

Test Step 8. Check the Duty Cycle of the

vehicle harness connector J1/P1, if necessary.

Accelerator Pedal Position Sensor at the

Sensor

C. Reconnect ECM connector J1/P1.

D. Turn the ignition key switch to the ON position.

Note: Performing certain steps within this procedure

requires the use of a multimeter that is capable of

E. Use ET to check for active diagnostic codes.

measuring a PWM duty cycle.

A. Turn the ignition key switch to the OFF position.

Expected Result:

One of the following diagnostic codes is still active

B. Remove the signal wire for the accelerator pedal

after the terminals for sensor power have been

position sensor (terminal "C") from P403. This is

disconnected:

the vehicle harness side of the accelerator pedal

position sensor connector.

41-03 8 Volt Supply Above Normal (21)

C. Install a breakout T with 3 terminals at the

41-04 8 Volt Supply Below Normal (21)

accelerator pedal position sensor connector

J403/P403.

Results:

D. Connect the multimeter probes to terminal "C"

(Accelerator Pedal Position) and terminal "B"

(Accelerator/Switch Sensor Common) of the

breakout T.

Repair: Perform the following repair:

E. While the duty cycle is being monitored on the

Check the battery voltage from P1:51 & 53

multimeter, depress the accelerator pedal and

(Unswitched +Battery) to P1:65 & 67 (-Battery).

release the accelerator pedal.

The measured voltage should be in one of the

following ranges:

For 12 Volt Systems, the voltage should be

between 11.0 VDC and 13.5 VDC.

For 24 Volt Systems, the voltage should be

between 22.0 VDC and 27.0 VDC.