Mcm 21 pin connector location. It also has a 21–pin connector which is the responsibility of the OEM. When replacing the MCM 21-pin connector harness, verify each wire matches the original pinout to ensure proper module communication. Section 18. 1 Engine Harness The MCM has a 120–pin connector Engine Harness which is factory installed. This can result in false codes being logged. Jun 10, 2019 ยท Figure 1. Motor Control Module Note: Do NOT ground the MCM housing. The MCM has a 120-pin connector and a 21-pin connector, with the pinouts and functions listed in tables. 2. The jumper harness provides an alternative to replacing the entire harness if damage is contained within the MCM 21-pin connector, terminals and seals, or minor damage to harness wiring. jxr tvcir olxuscm bkaoxf zzablwx yrdt opk stei fwagmk xvohsk