This cold be an ecm problem so here is the proper way to check to see if it is or notat least for the speed sensor. Diagnosis & Repair
1. Check speedometer operation. If speedometer is operating properly, go to next step. If speedometer is not operating properly, check for open or short in VSS circuit. See SYSTEM/COMPONENT TESTS
article. Repair as necessary.
2. Access ECM behind glove box. Turn ignition off. Disconnect ECM E10 connector. See Fig. 6 . Using DVOM, check for continuity between ground and terminal No. 12 (Violet/Yellow wire) at ECM E10
connector. If continuity does not exist, go to next step. If continuity exists, locate and repair short to ground in Violet/Yellow wire between ECM and instrument cluster.
3. Measure voltage between ground and terminal No. 12 (Violet/Yellow wire) at ECM E10 connector. If voltage is 9 14 volts, go to next step. If voltage is not 9 14 volts, locate and repair open in Violet/Yellow
wire between junction block No. 3, located behind instrument cluster, and ECM.
4. Check for open in Violet/Yellow wire between junction block No. 3 and instrument cluster. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, then replace ecu.
Make sure to check the ground for the ecu it is a white/black wire on left side of manifold, make sure it is NOT corroded or dirty. You might have a trasn guy look at this as you may have an internal trans problem as well. But keep in mind any type of engine problem will effect the trans. You other sensor is for O/D it h as a th/blu an dyel/blu wire leading to it. You might try to see what resistance the o/d sensor is giving. Test a new one at an autoparts store then see what yours is. If it's within range then suspect a overdrive clutch problem. The 720 code may be a clutch/seal problem as well
Monday, April 16th, 2012 AT 6:01 PM