Test Step 2. Connect ET and Check for Active Diagnostic Codes

141

TM 9-2320-312-24-2

Troubleshooting Section

A. Thoroughly inspect ECM engine harness

Expected Result:

connector J2/P2, boost pressure sensor

Select the condition of the following codes:

J200/P200, engine oil pressure sensor

J201/P201, atmospheric pressure sensor

232-03 5 Volt Supply Above Normal (21)

J203/P203 and Injection actuation pressure

sensor J204/P204. Refer to Troubleshooting,

232-04 5 Volt Supply Below Normal (21)

"Electrical Connectors - Inspect" for details.

B. Perform a 45 N (10 lb) pull test on each of the

Results:

wires in the ECM connector that are associated

Active Proceed to Test Step 3.

with the +5 V engine pressure sensor supply:

+5 V engine pressure sensor terminal 2

Logged ONLY Proceed to Test Step 5.

(G828-WH)

Not active or logged The +5 V supply is

engine pressure sensor common terminal 3

operating correctly at this time. STOP.

(G829-GN)

Test Step 3. Disconnect the ECM Engine

Harness Connector from the ECM.

Refer to Illustration 22.

C. Check the ECM connector (allen head screw) for

A. Connect ET to the cab data link connector.

the proper torque of 6.0 Nm (55 lb in).

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

D. Check the harness and wiring for abrasion and

pinch points from the sensors back to the ECM.

C. Disconnect ECM engine harness connector

J2/P2.

Expected Result:

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

All connectors, pins and sockets should be

completely coupled and/or inserted and the harness

E. Access the "Active Diagnostic Code" screen

and wiring should be free of corrosion, abrasion

onET. Check for one of the following active

or pinch points.

diagnostic codes:

Results:

232-03 5 Volt Supply Above Normal (21)

OK Proceed to Test Step 2.

232-04 5 Volt Supply Below Normal (21)

Not OK

Note: When ECM engine harness connector J2/P2

is disconnected and the ignition key switch is in the

Repair: Perform the following repair:

ON position, open circuit diagnostic codes will be

active or logged for all of the engine sensors. This

Repair the connectors or wiring and/or replace

is normal. The codes for the 5 Volt supply should

the connectors or wiring. Ensure that all of the

not be active.

seals are properly in place and ensure that the

connectors are completely coupled.

Expected Result:

Verify that the repair eliminates the problem.

The +5 V diagnostic code is active when the ECM

engine harness connector is disconnected.

STOP.

Results:

Test Step 2. Connect ET and Check for

Active Diagnostic Codes.

Yes Disconnecting the engine harness does not

eliminate the active +5 V sensor diagnostic code.

A. Connect Caterpillar Electronic Techinician (ET) to

the cab data link connector.

Repair: Perform the following diagnostic

procedure:

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

1. Temporarily connect a test ECM. Only connect

C. Monitor the "Active Diagnostic Code" screen of

ECM harness J1/P1.

ET. Check and record active diagnostic codes.

2. Recheck for an +5 V diagnostic code when

Note: Wait at least 15 seconds in order for the

the engine harness is disconnected.

diagnostic codes to become active.