Diagnostic Aids
Typical causes of no communication with the EBCM:
- Poor terminal contact at the EBCM
- Loss of EBCM ground to terminal 8 and 24
- Loss of battery voltage at EBCM terminals 9 and/or 25
- Loss of ignition voltage at EBCM 4
- Open/grounded data line
- Data line with high resistance
No Communication with Electronic Brake Control Module
| Step |
Action |
Value(s) |
Yes |
No |
| 1 |
Did you perform the Diagnostic System Check - Vehicle? |
- |
Go to Step 2 |
Go to Diagnostic System Check - Vehicle |
| 2 |
- Turn the ignition switch OFF.
- Disconnect the electronic brake control module (EBCM) harness.
- Connect a voltmeter to the EBCM harness terminal 9 and then to body ground.
Does the voltage measure within the specified range? |
B+ |
Go to Step 4 |
Go to Step 3 |
| 3 |
- Repair the source of the low voltage to terminal 9.
- Inspect for an open fuse, poor terminal contact, or a grounded wire.
Did you find and correct the condition? |
- |
System OK |
- |
| 4 |
Connect a voltmeter to the EBCM harness terminal 25 and then to the body ground.
Does the voltage measure within the specified range? |
B+ |
Go to Step 6 |
Go to Step 5 |
| 5 |
- Repair the source of the low voltage to terminal 25.
- Inspect for an open fuse, poor terminal contact, or a grounded wire.
Did you find and correct the condition? |
- |
System OK |
- |
| 6 |
- Turn ON the ignition switch.
- Connect a voltmeter to the EBCM harness terminal 4 and then to body ground.
Does the voltage measure within the specified range? |
B+ |
Go to Step 8 |
Go to Step 7 |
| 7 |
- Repair the source of the low voltage to terminal 4.
- Inspect for an open fuse, poor terminal contact, or a grounded wire.
Did you find and correct the condition? |
- |
System OK |
- |
| 8 |
- Turn the ignition switch OFF.
- Connect an ohmmeter to the EBCM harness terminal 8 and 24 and then to body ground.
Does the resistance measure less than the specified value? |
2 Ω |
Go to Step 10 |
Go to Step 9 |
| 9 |
- Repair the source of the high resistance between terminal 8 and 24.
- Find and inspect the ground location where the circuit is secured to body ground.
Did you find and correct the condition? |
- |
System OK |
- |
| 10 |
- Turn OFF the ignition switch.
- Verify the EBCM harness is still disconnected from the EBCM.
- Connect an ohmmeter to the EBCM harness terminal 7 and the data link connector (DLC) terminal 7.
Does the resistance measure less than the specified value? |
2 Ω |
Go to Step 12 |
Go to Step 11 |
| 11 |
Repair the source the high resistance between terminal 7 and DLC terminal 7.
Did you complete the repair? |
- |
System OK |
- |
| 12 |
- Turn the ignition switch OFF.
- Verify the EBCM harness is still disconnected.
- Connect an ohmmeter to the EBCM harness terminal 7 and then to body ground.
Does the resistance measure OL, open circuit? |
- |
Go to Step 14 |
Go to Step 13 |
| 13 |
Find and repair the short to ground on the data line.
Did you find and correct the condition? |
- |
System OK |
- |
| 14 |
Replace the EBCM.
Did you complete the replacement? |
- |
System OK |
- |