789D CMD Off-Highway Truck Chassis Electronic Control System (Command For Hauling) Caterpillar

MID 087 - Chassis ECM

CID 2250 - Brake Accumulator Purge Solenoid

FMI 03 - Voltage Above Normal

Illustration 1	g06351805
Brake accumulator purge solenoid circuit

This diagnostic code indicates the chassis ECM detects the brake accumulator purge solenoid circuit voltage is above normal.

The following can cause this code:

• Solenoid failure

• Shorted energizer circuit

• ECM failure

Note: The following test procedure may create other diagnostic codes. Ignore these created codes and clear these created codes after the original diagnostic code has been corrected.

System Response:

• A Level 1 Warning occurs

Test Step 1. CHECK THE DIAGNOSTIC CODE

1. Turn off the keyswitch and the disconnect switch.

2. Inspect the harness.

   Clean the harness connector contacts.

   Inspect the harness connector contacts for corrosion or damage.

   Inspect the wire insulation for damage caused by heat, corrosion, or chafing.

3. Perform a 45 N (10 lb) pull test on each circuit wire.

4. Reconnect all harness connectors.

   Verify that the connectors are fully seated and the clips are fastened.

5. Check for intermittent problems. Using Cat^® Electronic Technician (Cat ET), perform a wiggle test on the harness.

6. Turn on the disconnect switch and the keyswitch.

7. Operate the machine.

8. Check CID 2250 FMI 03 status.

Expected Result:

CID 2250 FMI 03 is not active.

Results:

• OK - CID 2250 FMI 03 is not active.

  Repair: The initial diagnostic code was probably caused by a poor connection at one of the connectors that was checked.

  Resume normal operation.

  STOP

• NOT OK - CID 2250 FMI 03 is still active. Proceed to Test Step 2.

Test Step 2. CHECK FOR A SHORT

The disconnect switch and the keyswitch remain off.

1. Disconnect the harness from the solenoid.

2. Disconnect harness connectors J1 and J2 from the ECM.

3. At the harness connectors for the ECM, measure the resistance from contact J1-12 (wire U771-PK(Pink)) to all of the other contacts used in the J1 and J2 connectors for the ECM.

Expected Result:

Each resistance is greater than 5000 ohms.

Results:

• OK - Each resistance is greater than 5000 ohms. Proceed to Test Step 3.

• NOT OK - A resistance is less than 5000 ohms. There is a short between wire U771-PK(Pink)and the circuit with low resistance.

  Repair: Repair or replace the harness.

  STOP

Test Step 3. CHECK ECM OPERATION

The disconnect switch and the keyswitch remain off.

The harness connectors for the solenoid and ECM remain disconnected.

1. Disconnect the solenoid energizer circuit.

2. At the harness connector J1 for the ECM, use a 151-6320 Removal Tool to remove the following:

   • Solenoid wire U771-PK(Pink)

   • Socket at contact J1-12

3. Reconnect the ECM to the harness.

4. Turn on the disconnect switch and the keyswitch.

5. Check CID 2250 FMI 03 status.

Expected Result:

CID 2250 FMI 03 changes to CID 2250 FMI 05.

Results:

• OK - CID 2250 FMI 03 changes to CID 2250 FMI 05. The solenoid has failed.

  Repair: Repace the solenoid.

  STOP

• NOT OK - CID 2250 FMI 03 does not change to CID 2250 FMI 05. The ECM may have failed.

  Repair: Exit this procedure and perform this procedure again. Contact your technical communicator. If the ECM requires replacement, see Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP