8206noco.fm Page 176 Thursday, July 2, 1998 1:19 PM
SYMPTOM RELATED DIAGNOSTICS BUFFERED MPH (SPEEDOMETER SIGNAL)
Figure 292 — Diagnostic Procedure Flowchart
Test 1 Checking for an external fault When performing electrical tests, it is important to wiggle wires and connectors to identify intermittent connection problems.
1. Turn the ignition key to the OFF position. 2. Disconnect all external units at the buffered MPH external tie point (located near the accessory bus).
If a diagnostic blink code 4-3 is active, proceed to the MPH Sensor Diagnostic.
3. Test drive the vehicle.
If the speedometer is now working, there is a short in the external harness or component. Locate and repair the short. Retest to be sure the problem has been corrected. If the speedometer still does not work, proceed to Test 2.
This diagnostic procedure starts from a customer complaint that the speedometer is not working.
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