The DDEC III/IV engine sensor harness for vehicle engines was originally equipped with five metal retaining clips and was secured to the engine cylinder block with bolts. Effective with engines built in May of 1995, three of the metal clips were replaced by three plastic push-in clips.
Due to a hardware change made in October of 1995 to the DDEC ® III ECM, a path to ground can arise during ECM powerdown which may allow unintended engine cranking.
Unintended engine cranking can occur if all of the following conditions exist:
- The engine has an ECM manufactured between October of 1995 and September of 1996.
- The engine is equipped with the Optimized Idle ™ feature.
- The ignition remains turned on while battery power is removed from the ECM during servicing.
Note: This condition will not occur on engines manufactured after September of 1996.
To address this concern and eliminate the potential for unintended engine cranking under the conditions listed above, an Optimized Idle Starter Relay Harness Overlay Service Kit was released for engines with ECM’s manufactured between October of 1995 and September of 1996.
