2010 Cadillac CTS Sedan AWD V6-3.0L Page 1758

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1758

Note: Testing for the following steps is performed on the fuel injector side of the multi-way harness connector. It may be necessary to

remove the intake manifold to isolate the condition.

4. Ignition OFF, measure the resistance between the appropriate high voltage supply circuit and ground. The DMM should display OL ohm.

瀚慖f less than the specified range, test the high voltage supply circuit and the high voltage control circuit for a short to ground. If the

circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).

5. Test for 2-3 ohm between the appropriate high voltage supply circuit and high voltage control circuit.

瀚慖f less than the specified range, test for a short between the high voltage supply circuit and high voltage control circuit. If the

circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).

瀚慖f greater than the specified range, test the high voltage supply circuit and high voltage control circuit for an open/high resistance. If the

circuits/connections test normal, test or replace the appropriate Q17 fuel injector.

Component Testing

Note: The DMM and test leads must be calibrated to 0 ohm in order to prevent misdiagnosis.

1. Remove the intake manifold and disconnect the appropriate Q17 fuel injector.

2. Test for 1.9-2.3 ohm at 20掳C (68掳F) between the high voltage supply circuit terminal 2 and the high voltage control circuit terminal 1 at the

Q17 fuel injector.

瀚慖f not within the specified range, replace the Q17 fuel injector.

3. Measure the resistance between each terminal at the Q17 fuel injector and the Q17 fuel injector housing/case. The DMM should display OL

ohm.

瀚慖f less than the specified value, replace the Q17 fuel injector.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Fuel Injector Replacement (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Injector/Service and Repair/Fuel Injector

Replacement)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming

P1255

DTC P1255 or P064A

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 P064A

- Fuel Pump Control Module Performance

DTC P1255

- Fuel Pump Control Module Driver Over-temperature

Circuit/System Description

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from

the ECM to the fuel pump control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received,

the fuel pump control module supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

Conditions for Running the DTC

The engine is running.