Test Step 2. Check for Active Diagnostic Codes -807640324

146

TM 9-2320-312-24-2

Troubleshooting Section

Result 3 There are no active diagnostic codes that

Expected Result:

are related to the accelerator pedal position sensor

circuit at this time, but a problem is suspected with

All connectors, pins and sockets should be

operation of the accelerator pedal position sensor

completely coupled and/or inserted and the harness

circuit.

and wiring should be free of corrosion, abrasion

or pinch points.

Results:

Result 1 Proceed to Test Step 3.

OK Proceed to Test Step 2.

Result 2 Proceed to Test Step 5.

Not OK

Result 3 Proceed to Test Step 3.

Repair: Perform the following repair:

Test Step 3. Check the Duty Cycle of the

Accelerator Pedal Position Sensor

Repair the connectors or wiring and/or replace

the connectors or wiring. Ensure that all of the

seals are properly in place and ensure that the

A. Connect ET to the cab data link connector.

connectors are completely coupled.

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

Verify that the repair eliminates the problem.

C. Monitor the duty cycle of the throttle sensor on

STOP.

ET. Access the following display screen in order:

Test Step 2. Check for Active Diagnostic

"Service"

Codes

"Calibrations"

A. Connect ET to the cab data link connector.

"Monitor Throttle Position Sensor"

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

Expected Result:

C. Monitor the active diagnostic code screen on ET.

The duty cycle is between 10 and 22 percent with

Check and record active diagnostic codes.

the accelerator pedal assembly in the Low Idle

position, and the duty cycle is between 75 and 90

Note: When the ECM automatically calibrates new

percent with the accelerator pedal assembly in the

duty cycle values for the low idle throttle position

High Idle position.

and the high idle throttle position the ECM assumes

22 percent duty cycle at low idle and 75 percent

Results:

duty cycle at high idle. As a result, you may notice

that the throttle position status reaches 100 percent

OK The accelerator pedal position sensor is

well before the accelerator pedal is fully depressed.

operating correctly. Proceed to Test Step 6.

This is normal. After some cycling of the accelerator

pedal to the high idle position, the ECM will adjust

Not OK The accelerator pedal position sensor

the calibration automatically. The ECM will adjust

circuit is not operating correctly. Proceed to Test

the calibration automatically provided that the high

Step 4.

idle stop position is within the 75 to 90 percent duty

cycle range, and the low idle is in the 10 to 22

Test Step 4. Check the Supply Voltage

percent duty cycle range. During normal operation,

at the Sensor for the Accelerator Pedal

you may also notice that more movement of the

Position Sensor

accelerator pedal is required for the throttle position

status to increase above 3 percent. You may also

observe that the status reaches the 100 percent

A. Install a breakout T with 3 terminals at the

value prior to the limit of the high idle position. This

accelerator pedal position sensor connector

is done in order to ensure that the throttle reaches

J403/P403.

these two critical points for engine operation.

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

Expected Result:

C. Measure the voltage at terminal "A" (+8 V) with

Result 1 Diagnostic Code 91-08 or 91-13 is Active.

reference to terminal "B" (Accelerator/Switch

Sensor Common).

Result 2 Diagnostic Code 41-03 or 41-04 is Active.