TROUBLESHOOTING FLASH CODE 12
[a] If active code 187/4 is logged, and code 187/3 only occurs when the throttle is moved
at or near full throttle (when connected), refer to section 12.3.3.
[b] If active code 187/3 is logged, and the code appears when the throttle is not at or near
full throttle (when connected), refer to section 12.3.4.
Perform these additional steps to check the calibration of the sensor:
1. Plug in the VSG throttle connector.
2. Turn ignition ON.
3. Plug in DDR.
4. Display VSG counts.
5. Dial throttle to Full Throttle.
[a] If the VSG counts are greater than 968, adjust the maximum throttle travel. If not
adjustable, replace the throttle control.
[b] If the VSG counts are less than 968, refer to section 12.3.4.
Return Circuit Check
Perform these steps to check the return circuit:
1. Place the transmission in neutral.
2. Turn ignition OFF.
3. Install a jumper wire between pin A (return #952) and pin B (signal #510/525) of the
VSG throttle harness connector.
4. Disconnect the vehicle harness connector at the ECM.
5. Enable VSG control. (This may require the ignition be turned on.)
6. Measure resistance between sockets C3 (#952) and D1 (#510) on the vehicle harness
connector. See Figure 12-2.
[a] If the resistance is less than or equal to 5 , refer to section 12.3.5.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION