8206code.fm Page 158 Tuesday, July 7, 1998 11:57 AM
DIAGNOSTIC CODE 7-1 Test 1
Test 3
Checking switch operation
Checking module connector
1. Using a diagnostic tool (Pro-Link or PC), check the status of the service brake switch as you engage and disengage the service brake with the ignition key in the ON position. Engage the service brake for at least 1 second.
If the service brake signal, displayed on the service tool, toggles properly and the fault is still active, replace the V-MAC II module. Retest to be sure the problem has been corrected. If the service brake signal, displayed on the service tool, toggles properly and the fault is inactive, proceed to Test 2. If the service brake signal, displayed on the service tool, does not toggle properly, always remaining ON or remaining OFF, proceed to Test 3.
Test 2 Checking the MPH Sensor Adjustment
Figure 258 — J2 Module Terminals and Connector
1. Turn the ignition key to the OFF position. 2. Disconnect the J2 connector from the V-MAC II module. 3. Check both sides of the connector for problems such as bent, loose, missing or corroded pins. Figure 257 — MPH Sensor
1. Check the MPH sensor adjustment. For proper adjustment, turn the sensor in by hand until it bottoms. Then back it out exactly 1 turn. Torque the jam nut to 15 lb-ft (20 N•m).
If the sensor is adjusted properly, drive the vehicle while monitoring road speed with a diagnostic tool (Pro-Link or PC). If the road speed on the diagnostic tool is erratic, replace the MPH sensor. Retest to be sure the problem has been corrected. If the road speed is not erratic, proceed to Test 4. Page 158
If the pins are damaged, replace the connector pins or the V-MAC II module. Retest to be sure the problem has been corrected. If the pins are in good condition, proceed to Test 6.
