8206noco.fm Page 190 Thursday, July 2, 1998 1:19 PM
SYMPTOM RELATED DIAGNOSTICS ENGINE BRAKE VERBAL COMPLAINT (continued) Test 4
1. Turn the ignition key to the OFF position.
Checking for an open between the engine brake relay and the V-MAC II module
2. Disconnect the J1B connector from the V-MAC II module. 3. Check for continuity between J1B connector pin P3 (the engine brake control relay) and pins 85 and 86 on one engine brake relay connector.
If there is continuity between 85 or 86 (but not both) and P3, repeat the procedure for every other engine brake relay. If all of the relay test results return to this step, proceed to Test 8. If there is no continuity, there is an open between either pin 85 and P3 or 86 and P3 (see the wiring schematic supplied with the vehicle). Locate and repair the open. Retest to be sure the problem has been corrected. If there is continuity between BOTH pins and P3, the wires leading to pins 85 and 86 are shorted, or there is a short in the relay connector body. Repair the short. Retest to be sure the problem has been corrected.
Figure 308 — Brake Relay Connector
Page 190
