2010 Cadillac CTS Sedan AWD V6-3.0L Page 1985

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1985

瀚慖f the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control

module.

瀚慖f the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace

the K27 fuel pump control module.

6. Perform the Fuel System Diagnosis (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component

Tests and General Diagnostics/Fuel System Diagnosis) to verify proper fuel pressure.

瀚慖f the fuel pressure is not normal, replace the G12 fuel pump

7. If all circuits test normal, replace the K27 fuel pump control module.

Repair Instructions

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

* Fuel Tank Fuel Pump Module Replacement - Right Side (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Pump/Service

and Repair/Fuel Tank Fuel Pump Module Replacement - Right Side)

* Control Module References (See: Testing and Inspection/Programming and Relearning)for fuel pump control module replacement, setup,

and programming

P2636

DTC P2636

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 Descriptor

DTC P2636

- Fuel Pump 2 Flow Insufficient

Circuit Description

The fuel tank on this vehicle is equipped with 2 fuel level sensors, one for each reservoir of the fuel tank. Fuel is transferred from the left side of the

fuel tank to the right side of the fuel tank in order to ensure all of the usable fuel volume is available. The fuel pump supplies a small amount of

pressurized fuel to the siphon jet pump through the fuel feed pipe. The pressurized fuel creates a venturi action inside the siphon jet pump. The

venturi action causes the fuel to be drawn out of the left side of the fuel tank. Fuel is then transferred from the left side of fuel tank to the right side

of fuel tank through the internal fuel transfer tube. This diagnostic tests for too large of a difference in fuel level between the left and right side of

the fuel tank. The DTC sets if the control module determines that the right side fuel level is less than a predetermined amount of the left side fuel

level.

The following table illustrates the difference between fuel level, resistance, and voltage:

Conditions for Running the DTC

* Before the engine control module (ECM) can report DTC P2636 failed, DTCs P0461, P0462, P0463, P2066, P2067, and P2068 must run and

pass.

* The ignition 1 signal parameter is between 10-18 volts.

* The engine speed is greater than 240 RPM.

* DTC P2636 runs continuously once the above conditions exist for greater than 4 minutes.

Conditions for Setting the DTC

The ECM detects that the right side fuel level is less than 11 percent and the left side fuel level is greater than 22 percent.