DTC 27, LCD Blanking Control CKT Open Or Shorted To Ground: Testing
- Note all stored current and history codes. Turn ignition switch to OFF position. Remove instrument cluster to expose cluster harness connector located in instrument panel carrier. Using adapter from Terminal Test Adapter Kit (J 35616-A), connect DVOM between cluster harness connector terminal A13 and ground. Check for continuity. If continuity is present, repair short to ground in LCD blanking control circuit. If continuity is not present, go to next step.
- Disconnect CCM Gray connector. Using adapter, connect DVOM between cluster harness connector terminal A13 and CCM Gray connector, terminal D11. Check for continuity. If continuity is not present, repair open in LCD blanking control circuit. If continuity is present, go to next step.
- Connect Red leads of Signal Generator/Instrumental Panel Tester (J 33431-B) to DVOM. Using ohmmeter feature of DVOM, set resistance on tester to 1150-1250 ohms by turning adjustment dials. Turn ignition switch to OFF position. Disconnect DVOM from tester. Using adapters from adapter kit, connect one lead of tester to cluster harness connector terminal A13 and other lead to terminal A16. Reconnect CCM Gray connector. Install Tech 1. Turn ignition switch to ON position. Using Tech 1, read CCM DTCs. If DTC 27 resets, check for poor connections at CCM. If connections are okay, replace CCM. If DTC 27 does not reset, go to next step.
- Check for intermittents in LCD blanking control circuit. If an open is present in LCD blanking control circuit, LCD portion of instrument cluster will be blank. If a short to ground is present in LCD blanking control circuit, LCD portion of instrument cluster will not update (will be frozen). If code is set as history, problem may be intermittent. Try to recreate fault while performing test by wiggling wiring and connectors. Check for poor connections at all connectors that may be causing intermittent condition. If wiring and connections are okay, replace instrument cluster.