Circuit Description
Ignition voltage is supplied to terminal C2 of the Electronic Brake Control Relay. The above enables the EBCM/EBTCM to energize the pullin coil by completing the ground circuit at connector C1 terminal A11 of the EBCM/EBTCM. The magnetic field created closes the Electronic Brake Control Relay contacts. The magnetic field also allows battery voltage and current through the Electronic Brake Control Relay terminal C1 to be supplied to the EBCM/EBTCM through connector C2 terminal C and to the Brake Solenoid Valves through S279.
Conditions for Setting the DTC
DTC C1218 can set after the EBCM/EBTCM commands the Electronic Brake Control Relay on.
The test monitors the availability of current/voltage to the motors and solenoids.
The above malfunction indicates voltage is not available to the motors and solenoids. The malfunction may not allow ABS/TCS operation.
Action Taken When the DTC Sets
| • | A malfunction DTC stores. |
| • | The ABS/TCS disables. |
| • | The amber ABS/TCS warning indicators turn on. |
| • | The red BRAKE warning indicator turns on if the rear piston in the ABS brake motor pack is not in the home position. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTC function is used. |
| • | 100 drive cycles pass with no DTCs detected. |
Diagnostic Aids
The following conditions may cause an intermittent malfunction:
| • | A poor connection |
| • | Rubbed-through wire insulation |
| • | A broken wire inside the insulation |
Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Refer to the Scan Tool manual or Scan Tool Diagnostics located in this section for the procedure.
Thoroughly inspect any circuitry that may be causing the intermittent complaint for the following conditions:
| • | Backed out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal-to-wiring connections |
| • | Physical damage to the wiring harness |
Clear the DTCs after completing the diagnosis. Test drive the vehicle for three drive cycles in order to verify that the DTC does not reset. Use the following procedure in order to complete one drive cycle:
- Start the vehicle.
- Drive the vehicle over 16 km/h (10 mph).
- Stop the vehicle.
- Turn the ignition to the OFF position.
Important: Zero the J 39200 test leads before making any resistance measurements.
Step | Action | Value(s) | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | |||||||||||
2 |
Does the Scan Tool indicate that the electronic brake control relay is OFF and that the switched battery voltage is equal to the specified value? | 0.00 V | Go to Step 12 | Go to Step 3 | ||||||||||
3 |
Is any voltage present at the 24-way EBCM/EBTCM harness connector C1 terminal A11? | -- | Go to Step 9 | Go to Step 4 | ||||||||||
4 |
Is the resistance within the specified range? | 0-95ohms | Go to Step 5 | Go to Step 10 | ||||||||||
5 | Use the J 39200 in order to measure the resistance between the electronic brake control relay terminal A2 and the electronic brake control relay terminal C1. Is continuity present across the contact side of the electronic brake control relay? | -- | Go to Step 10 | Go to Step 6 | ||||||||||
6 |
Are there signs of poor terminal contact, corrosion, or damaged terminals? | -- | Go to Step 8 | Go to Step 7 | ||||||||||
7 |
Does DTC C1218 set as a current DTC? | -- | Go to Step 11 | Go to Step 12 | ||||||||||
8 | Replace all of the terminals or connectors that exhibit signs of poor terminal contact, corrosion, or damaged terminal(s). Is the repair complete? | -- | -- | |||||||||||
9 | Repair the short to voltage in CKT 1632. Is the repair complete? | -- | -- | |||||||||||
10 | Replace the electronic brake control relay. Is the repair complete? | -- | -- | |||||||||||
11 | Replace the EBCM/EBTCM. Is the repair complete? | -- | -- | |||||||||||
12 | The system is functioning properly at this time. The malfunction may be intermittent or is not present at the time of testing. Is a concern still present? | -- | Go to Diagnostic Aids |
