Antilock Braking System (ABS)

DTC 63 BPM Valve Relay Malfunction (Part 1 Of 2):

DTC 63 BPM Valve Relay Malfunction (Part 2 Of 2):

DTC 63 BPM Valve Relay Malfunction:

CIRCUIT DESCRIPTION
The BPM valve relay has a dual function. With ignition "ON" and the relay coil not energized, the relay provides ground to the ABS warning lamp causing it to illuminate. This allows illumination of the ABS warning lamp when the EBCM is disconnected or disabled. With ignition "ON" and the relay coil energized, the relay supplies battery voltage to the valve solenoids. This allows the EBCM to control actuation and position of the valve solenoids by controlling the ground path. CKT 856 allows the EBCM to monitor the state of the BPM valve relay to compare with the requested state.

DTC 63 WILL SET WHEN
The BPM valve relay monitor is at B+ when the EBCM is not requesting it to be, or if the EBCM is requesting the BPM valve relay be energized and the BPM valve relay monitor voltage is less than 5 volts.

ACTION TAKEN
If a malfunction is detected which causes a BPM valve relay DTC 63 to set, antilock braking is disabled and the EBCM turns "ON" the ABS warning lamp for the remainder of the ignition cycle. If the malfunction is intermittent, the EBCM will enable the system at the next ignition cycle and a history DTC 63 will be present.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks for proper resistance of the relay coil.
2. Checks for the relay contacts stuck in the normally open position.
3. Checks for the relay contacts stuck in the normally closed position.
4. Checks for integrity of the circuitry internal to the BPM valve.
5. Checks for a good pump motor ground circuit.
6. Checks for an open in the BPM valve relay monitor circuit.
7. Checks for an open in the BPM valve relay coil switched ground circuit.
8. Checks for an open in the relay feed (coil battery feed) circuit.
9. Checks for a short to ground in the BPM valve relay monitor circuit.
10. Checks for a short to ground in the BPM valve relay coil switched ground circuit.
11. Checks for a short to ground in the relay feed (coil battery feed) circuit.
12. Checks for a short to B+ in the BPM valve relay monitor circuit.
13. Checks for a short B+ in the BPM valve relay coil switched ground circuit.
14. Checks for an open in the BPM valve battery feed circuit.
15. Checks for a short to ground internal to the BPM valve.
16. Checks for improper connections which may have set the DTC.
17. Checks for a DTC with may have been set falsely.

DIAGNOSTIC AIDS
All tests which require a connection to pinout box Pin 20 are using this pin as ground. This assumes the integrity of ground CKT 51 has been maintained.
A disconnected or improperly seated BPM valve connector may set this DTC.