| Subject: | Diagnostic Information for LS2, LS4 and LH6 Engines for Diagnostic Trouble Codes (DTCs) P0606, P0689, P1516, P1682 and/or P2176 That May Have Set Due to Low Battery Voltage Condition |
| Models: | 2005-2006 Buick Rainier |
| 2005-2006 Chevrolet Impala SS, Monte Carlo SS, SSR, Trailblazer SS |
| 2005-2006 GMC Envoy Denali, Envoy XL Denali |
| 2005-2006 Pontiac Grand Prix, GTO |
| with 5.3L or 6.0L V8 Engine (VINs C, M, H, U -- RPOs LS4, LH6, LS2) |
This bulletin is being published to aid technicians in the diagnosis of the following DTCs:
| • | P0606 -- Control Module Internal Performance |
| • | P0689 -- Engine Controls Ignition Relay Feedback Circuit Low Voltage |
| • | P1516 -- Throttle Actuator Control (TAC) Module Actuator Position Performance |
| • | P1682 -- Ignition 1 Switch Circuit 2 |
| • | P2176 -- Minimum Throttle Position Not Learned |
The above DTCs may have set under a low battery voltage condition during or prior to vehicle cranking, then starting. If these codes are present, and a low battery condition exists or the customer indicates that the vehicle has experienced a low battery
voltage condition, the technician should do the following:
- With a Tech 2®, observe the engine RPM and the control module voltage in freeze frame and failure records for the DTC(s) set. If the engine RPM is zero or lower than idle speed and the control module voltage indicates less than 9 volts,
this may indicate a low battery condition had occurred to cause these codes to set. The low battery condition should be diagnosed and corrected. Refer to SI for Battery Inspection/Test and/or Charging System Test.
- If the battery voltage is within the normal operating range, refer to the DTC(s) set in SI for further diagnosis.
- After the low voltage concern has been identified and addressed, clear the codes. Do not
replace the ECM for this concern or replace and ECM with any of the following part numbers:
