Circuit Description
Ignition voltage is supplied to terminal 85 of the Electronic Brake Control relay. The EBCM is then able to energize the pull-in coil by completing the ground circuit at EBCM connector C1 terminal D6. The magnetic field created closes the Electronic Brake Control relay contacts and allows battery voltage and current to be supplied to the EBCM. In addition, the EBCM supplies power to the motors and the ABS solenoids.
Conditions for Setting the DTC
DTC 1216 can set anytime after the Electronic Brake Control Relay is commanded ON. This test detects an open in the Electronic Brake Control Relay coil circuit. An open in this circuit will not allow the Electronic Brake Control Relay to be energized thus preventing power to the motors and solenoids.
A DTC C1286 will be set with DTC C1216 if the rear channel is not expected to be in the home position.
Action Taken When the DTC Sets
| • | A malfunction DTC stores. |
| • | The ABS disables. |
| • | The ABS warning indicator turns ON. |
| • | The red BRAKE warning lamp is turned ON if the rear piston in the motor pack is not expected to be in the home position. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used. |
| • | 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF. |
Diagnostic Aids
The following conditions may cause an intermittent malfunction:
| • | A poor connection |
| • | Rubbed-through wire insulation |
| • | A broken wire inside the insulation |
An open in CKT 9X01 will not allow the Electronic Brake Control relay to be energized thus preventing power to the EBCM, and from the EBCM to the motors and ABS solenoids.
Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.
If the frequency of the malfunction is high, but is currently intermittent, inspect for high coil resistance. Use a J 39200 in order to measure for high coil resistance by measuring between Electronic Brake Control Relay terminal 85 and terminal 86. If the resistance shows greater than 95 ohms, replace the Electronic Brake Control Relay.
Thoroughly inspect any circuitry that may be causing the intermittent complaint for the following conditions:
| • | Backed out terminals |
| • | Improper mating |
| • | 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. Refer to the J 39200 user's manual.
Step | Action | Value(s) | Yes | No | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |||||||||||||
2 |
Do not start the engine. Does the Scan Tool indicate that the Electronic Brake Control Relay is ON, and is the voltage equal to or greater than the specified voltage? | 10 V | ||||||||||||||
3 | Use the J 39200 in order to measure the voltage between the Electronic Brake Control Relay connector terminal 85 and ground. Is the voltage equal to or greater than the specified voltage? | 10 V | ||||||||||||||
4 | Use the J 39200 in order to measure the voltage between the Electronic Brake Control Relay connector terminal 86 and ground. Is the voltage equal to or greater than the specified voltage? | 10 V | ||||||||||||||
5 |
Do not start the engine. Is the voltage equal to or greater than the specified voltage? | 10 V | ||||||||||||||
6 |
Are there signs of poor terminal contact, corrosion, or damaged terminals? | -- | ||||||||||||||
7 |
Is the resistance within the specified range? | 0-2 ohms | ||||||||||||||
8 |
Do not start the engine. Does DTC C1216 set as current DTC? | -- | ||||||||||||||
9 |
Do not start the engine. Is the voltage equal to or greater than the specified voltage? | 10 V | ||||||||||||||
10 | Remove and inspect the REAR DEFG Fuse (15A). Is the fuse open? | 0-2 ohms | ||||||||||||||
11 |
Is the resistance within the specified range? | 0-2 ohms | ||||||||||||||
12 |
Is the resistance within the specified range? | OL (Infinite) | ||||||||||||||
13 |
Is the resistance within the specified range? | 65-95 ohms | ||||||||||||||
14 | Repair the open or high resistance in CKT 1Y04 and 1Y03. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||
15 | Repair the open or high resistance in the following circuits and components:
Refer to Power Distribution Schematics in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||
16 | Replace all of the terminals that display signs of poor terminal contact, corrosion, or damaged terminal(s). If the Electronic Brake Control Relay displays signs of corrosion, replace the Electronic Brake Control Relay. Refer to Electronic Brake Control Relay Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||
17 | Repair the open or high resistance in CKT 9X01. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||
18 | Repair the short to ground in CKT 1Y04 or 1Y03. Is the repair complete? | -- | -- | |||||||||||||
19 | Replace the fuse block REAR DEFG Fuse (15A) with a known good fuse. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||
20 | Replace the Electronic Brake Control Relay. Refer to Electronic Brake Control Relay Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||
21 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||
22 | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. Is the action complete? | -- | System OK | -- |
