P042F Exhaust Gas Recirculation Control Stuck Closed

OBD-II Trouble Code - P042F - Data Sheet

P042F - Exhaust gas recirculation control stuck closed

What does DTC P042F mean?

This is a Generic Transmission Diagnostic Trouble Code (DTC) applicable to OBD-II vehicles. This may include, but is not limited to, Ford, Chevrolet / GM / Cummins, Dodge / Ram, Isuzu, Pontiac, Toyota, BMW, Mercedes, etc. While general, exact repair steps may vary by year, brand and models. and transmission configuration.

If your vehicle has stored a code P042F, it means that the powertrain control module (PCM) has detected a problem with the exhaust gas recirculation (EGR) valve control system.

In the case of P042F, the valve appears (to the PCM) stuck in the closed position. The designation A refers to a specific position or stage of the down-regulation of the EGR valve, which is explained below.

The EGR system is responsible for allowing the engine to consume some of the unburned fuel from the exhaust system. Exhaust Gas Recirculation (EGR) is essential to reduce harmful levels of nitrogen oxide (NOx) from gasoline and diesel engines.

The centerpiece of the exhaust gas recirculation system is an electronically controlled valve (EGR) that opens to allow exhaust gas to flow back into the engine intake. The PCM uses inputs from the Throttle Position Sensor (TPS), Vehicle Speed ​​Sensor (VSS), and Crankshaft Position (CKP) sensor to determine when conditions are suitable to open / close the EGR valve.

Vehicles with this code are equipped with an exhaust gas recirculation lowering valve. The EGR down valve works in stages depending on the throttle opening, engine load and vehicle speed.

On some models, the position of the EGR valve plunger is also monitored by the PCM. If the desired EGR valve position (by PCM command) differs from the actual position, a P042F code will be stored and a malfunction indicator lamp (MIL) may illuminate. Other vehicles use data from the Manifold Air Pressure (MAP) and / or Differential Pressure Feedback (DPFE) EGR sensor to determine if the EGR valve is in the desired position (or not). Most vehicles will take several ignition cycles (with a malfunction) before the MIL illuminates.

Photo of EGR valve:

What is the severity of this DTC?

Since the closed position of the exhaust gas recirculation valve does not pose a serious problem in terms of controllability, the P042F code can be reviewed at the earliest opportunity.

What are some of the symptoms of a P042F code?

Symptoms of a P042F EGR trouble code may include:

• Most likely there will be no symptoms with this code
• Slightly reduced fuel efficiency

What are some of the common causes for the code?

Reasons for this P042F code may include:

• Defective exhaust gas recirculation valve
• EGR solenoid / valve defective
• Open or short circuit in the wiring / connectors in the control circuit of the exhaust gas recirculation system
• Defective DPFE sensor
• Defective EGR valve position sensor
• Faulty PCM or PCM programming error
• EGR flow control valve
• EGR volume control solenoid harness is open or shorted.
• Faulty EGR flow control circuit solenoid circuit
• EGR temperature sensor and its circuit

What are some steps to troubleshoot the P042F?

A diagnostic scanner, digital volt / ohmmeter, and a reliable source of vehicle information are among the tools required to diagnose the P042F code.

A visual inspection of all EGR wiring and connectors is the perfect harbinger of a P042F code diagnosis. Repair or replace any corroded or burnt components as necessary.

Then connect the scanner to the diagnostic port and retrieve all stored codes and freeze frame data. Make a note of this as it will be useful if P042F is an intermittent code. Now clear the codes and test drive the vehicle to make sure the code is cleared.

If the code is cleared, connect the scanner and observe the data flow. Check the desired EGR position (usually measured as a percentage) and the actual EGR position shown on the data flow display. They should be identical within a few milliseconds.

The DPFE and MAP sensors should reflect the opening and / or closing of the EGR valve (optional). If MAP or DPFE sensor codes are present, they may be associated with P042F and should be treated as such.

If the desired EGR position differs from the actual position, follow the manufacturer's recommendations for testing the EGR actuator solenoids with DVOM. The exhaust gas recirculation lowering valves can use multiple solenoids to influence the full range of operation of the exhaust gas recirculation system.

If a DPFE sensor is used in the exhaust gas recirculation system for the vehicle in question, follow the manufacturer's recommendations for testing it. Connector pin tables and vehicle wiring diagrams found in your vehicle information source will aid testing. Replace faulty sensors if necessary and retest the system.

The DVOM can be used to test individual circuits between the PCM connector and the EGR valve connector. All linked controllers must be disconnected from the circuit before testing.

• After repairs have been completed, let the PCM go into readiness mode before assuming they were successful.

Codes related to P042F

• P0401 Insufficient EGR Exhaust Flow
• P0404 EGR circuit range/performance
• P042E EGR control A stuck open
• P0490 Exhaust Gas Recirculation A Control Circuit High

How to fix DTC P042F EGR stuck closed Ford Ranger

Need more help with your P042F code?

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