No Communication With EBCM

Circuit Description
Serial data is transmitted/received by the EBCM through terminal Al. The EBCM is supplied switched ignition voltage through connector C1terminal A9 and battery feed voltage through connector C1terminal B12. The EBCM ground is provided through connector C2 terminal D.

Diagnostic Aids
Communication with the EBCM is not possible when excessive resistance exists in the following components:
- The ground
- The power supply circuits
If communication with the EBCM is not possible, perform the following actions:
- Verify that the EBCM ground connection is good.
- Verify that no excessive resistance exists in any of the power supply circuits.

Test Description
5. This test checks for high resistance in the EBCM ground circuit.
6. This test checks for an open in the EBCM battery feed circuit.
7. This test checks for an open or high resistance in the EBCM switched ignition circuit.
8. This test checks for an open or high resistance in the EBCM serial data circuit.
9. This test checks for a short to ground in the EBCM serial data circuit.
11. This test checks for a short to ground in the EBCM battery feed circuit.
12. This test checks for a short to ground in the EBCM switched ignition circuit.