C0282

DTC C0282, C0285, or C0286





Test 1-9





Test 10-16

Circuit Description
The Brake Pressure Modulator Valve (BPMV) contains a Medium Pressure Accumulator (MPA). The MPA provides pressure to the front brakes during certain VSES events. The MPA switch is included to monitor the status of the pressure accumulator. The MPA switch is open when the MPA is uncharged.
The integrity of the MPA switch is tested by the EBCM. The MPA is partially discharged during system initialization to open the switch, and then recharged to close the switch. The EBCM continues to monitor the switch to ensure the MPA remains charged. Provided the VSES is not activated, the MPA should remain charged for the entire ignition cycle. If the MPA switch opens within 5 minutes of closing, a fast leakdown condition is detected. If the MPA switch opens after 5 minutes has passed, a slow leakdown condition is detected.

Conditions for Running the DTC
C0282 and C0285
^ The ignition is ON.
^ The vehicle speed is greater than 12 km/h (8 mph).

C0286
^ The ignition is ON.
^ The MPA switch is closed.
^ The diagnostic tests for DTC C0282 and C0285 have ran and passed.

Conditions for Setting the DTC
C0282
The MPA switch remains closed when the MPA is discharged for 1-2 seconds, depending on ambient temperature.

C0285
During the MPA charging period, the MPA switch does not close within the time indicated on the following table.

Ambient Temperature Fault Timer
Greater than 32°F 86 sec
Between -22°F and 32°F 170 sec
Less than -22°F 230 sec

C0286
Any of the following conditions may cause DTC CO286 to set.
^ The EBCM detects 2 fast MPA leakdowns during the system initialization period.
^ The EBCM detects 3 fast MPA leakdowns after the system has initialized.
^ The sum of the fast and slow MPA leakdowns detected after the system has initialized equals 7.

Action Taken When the DTC Sets
^ The EBCM disables the VSES.
^ The message center displays the SERVICE STABILITY SYSTEM message.

Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids
Thoroughly inspect the MPA switch jumper harness for any condition that may cause an intermittent malfunction.
An intermittent DTC may be difficult to verify since the DTC may take a substantial amount of time to set. If a DTC continues to set intermittently, remove the MPA switch and activate the switch by pressing and releasing the plunger. Ensure the plunger movement is smooth and that the plunger releases readily without sticking. Observe the MPA Switch input on the scan tool to verify that the status changes from Uncharged to Charged every time the switch is pressed. Replace the BPMV if no fault is found in the switch, circuitry or connections.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
4. This step simulates an open MPA switch.
5. This step simulates a closed MPA switch.
6. This step tests the MPA switch by closing the switch manually.
7. This step tests the MPA switch by ensuring the switch plunger is in the open position.