Exhaust Brake Circuit

265

TM 9-2320-312-24-2

Troubleshooting Section

Repair: Perform the following repair:

1. Temporarily connect a test ECM.

1. Repair the faulty wiring harness or replace the

faulty wiring harness.

2. Remove all jumpers and replace all connectors.

2. Clear all diagnostic codes.

3. Recheck the system for active diagnostic

codes.

3. Verify that the repair eliminates the problem.

4. Repeat the test step.

STOP.

Not OK Restart this procedure and carefully

5. If the problem is resolved with the test ECM,

reconnect the suspect ECM.

perform each step. STOP.

6. If the problem returns with the suspect ECM,

i01617893

replace the ECM.

Exhaust Brake Circuit - Test

7. Verify that the repair eliminates the problem.

SMCS Code: 1093-081

STOP.

System Operation Description:

Test Step 8. Bypass the Harness Wiring

Between the ECM and the Sensor

Use this procedure under the following situation:

Connector.

Use this procedure to determine if the circuit for the

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

exhaust brake (output 3) is operating correctly.

B. Disconnect the connector for the ECM harness,

The following background information is related

and the sensor connector.

to this procedure:

C. Remove the sensor signal wire from the ECM

The exhaust brake relay circuit is provided by

connector.

the ECM. The circuit indicates that conditions

are acceptable for an exhaust brake to operate.

D. Remove the signal wire (terminal 1) from the

Operation of the exhaust brake is inhibited during

sensor connector on the engine harness.

undesirable engine operating conditions.

E. Fabricate a jumper wire that is long enough to

When the cruise control on/off switch is in the

reach from the ECM to the sensor connector with

OFF position, the following conditions exist:

Deutsch sockets on both ends.

All of the following conditions must be met in order

F. Insert one end of the jumper into the ECM

to ensure the proper operation of the exhaust brake:

Connector. Insert the other end of the jumper

into the sensor connector of the engine harness.

Engine speed is above 1000 rpm.

G. Reconnect the connector for the ECM harness

The accelerator pedal position is less than seven

and the sensor connector.

percent.

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

The clutch pedal is released.

I. Monitor the "Active Diagnostic Code" screen for

The switch for the exhaust brake is on.

either the open circuit diagnostic code for the

sensor or the short circuit diagnostic code for

The PTO on/off switch is off.

the sensor.

When the cruise control on/off switch is in the ON

Expected Result:

position, the following conditions exist:

The diagnostic code disappears when the jumper

"Exhaust Brake Mode" Parameter

is installed.

Results:

OK There is a problem in the wiring harness.