P0252-INJECTION PUMP FUEL METERING CONTROL CIRCUIT PERFORMANCE

P0252-INJECTION PUMP FUEL METERING CONTROL CIRCUIT PERFORMANCE

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Fuel Quantity Solenoid (FQS) works in tandem with the Fuel Pressure Regulator (FPR) to control fuel volume and pressure in the Fuel Rail. The FQS is positioned in the inlet side of the High Pressure Delivery Pump (HPDP). The FQS receives 12 Volts from the Totally Integrated Power Module (TIPM) and a duty-cycle ground signal from the Powertrain Control Module (PCM). The FQS is normally open, so when the FQS is not actuated (no ground signal from the PCM), the HPDP inlet passage is open allowing full fuel flow to the pumping chambers inside the HPDP. When the PCM grounds the FQS control signal the FQS closes the fuel inlet passage, preventing fuel from entering the pumping chambers. The FPR is positioned at the return passage of the Fuel Rail. The solenoid receives 12 Volts from the TIPM and a duty-cycle ground signal from the PCM. The FPR is normally open and when the solenoid is not actuated (no ground signal from the PCM), the Fuel Rail return passage opens allowing fuel pressure in the rail to escape into the return circuit and on to the Fuel Tank. When the PCM grounds the FPR control signal, the solenoid valve closes allowing fuel pressure to build in the rail.

• When Monitored:

  With the ignition on and the Fuel Quantity Solenoid commanded off.

• Set Condition:

  The Powertrain Control Module (PCM) detects that the (K365) Fuel Quantity Solenoid Control circuit is shorted to ground for 0.2 second.

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

1. DTC IS ACTIVE

• Go To 2

• Perform the INTERMITTENT DTC diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

2. CHECK THE (F342) FUSED ASD RELAY OUTPUT CIRCUIT FOR AN OPEN/HIGH RESISTANCE

• Go To 3

• Repair the (F342) Fused ASD Relay Output circuit for an open circuit or short to ground condition.
• Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
  

3. CHECK THE (K365) FUEL QUANTITY SOLENOID CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE

• Go To 4

• Repair the (K365) Fuel Quantity Solenoid Control circuit for an open or high resistance.
• Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
  

4. FUEL QUANTITY SOLENOID

• Replace the Fuel Control Actuator in accordance with the service information.
• Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

• Go To 5

5. POWERTRAIN CONTROL MODULE

• Repair as necessary.
• Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

• Replace the Powertrain Control Module in accordance with the service information.
• Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).