2010 Cadillac CTS Sedan AWD V6-3.6L Page 1563
3. Connect a test lamp between the control circuit terminal 13 and the ignition circuit terminal 20.
4. Command the MIL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
瀚慖f the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace
the K20 ECM.
5. If all circuits test normal, replace the P16 instrument cluster.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM and instrument cluster replacement, setup, and
programming
P0651
DTC P0641-P0643, P0651-P0653, or P0697-P0699 (ECM, LLT)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0641
- 5 V Reference 1 Circuit
DTC P0642
- 5 V Reference 1 Circuit Low Voltage
DTC P0643
- 5 V Reference 1 Circuit High Voltage
DTC P0651
- 5 V Reference 2 Circuit
DTC P0652
- 5 V Reference 2 Circuit Low Voltage
DTC P0653
- 5 V Reference 2 Circuit High Voltage
DTC P0697
- 5 V Reference 3 Circuit
DTC P0698
- 5 V Reference 3 Circuit Low Voltage
DTC P0699
- 5 V Reference 3 Circuit High Voltage
Circuit/System Description
The engine control module (ECM) has 3 5 V reference circuits. The ECM provides the 5 V reference to various sensors. Each reference circuit
provides a 5 V reference for more than one sensor. An open, short to ground, or short voltage on one of the 5 V reference circuits can affect all the
components connected to that 5 V reference circuit. The ECM monitors the voltage on the 5 V reference circuits.
Conditions for Running the DTC
* The ignition is ON for more than 3 s.
* DTCs P0641, P0642, P0643, P0651, P0652, P0653, P0697, P0698, and P0699 run continuously when the above condition is met.
