P042E Exhaust Gas Recirculation Control Stuck Open

P042E Exhaust Gas Recirculation Control Stuck Open

OBD-II DTC Datasheet

Exhaust Gas Recirculation Regulator Stuck Open

What does this 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 the code P042E, 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 P042E, the valve appears (to the PCM) stuck open. The designation A refers to a particular 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 P042E code will be stored and a malfunction indicator lamp (MIL) may illuminate. 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?

Conditions that result in a P042E code being stored can also lead to severe handling problems. For this reason, the P042E code should be corrected urgently.

What are some of the symptoms of the code?

Symptoms of a P042E EGR DTC may include:

• Rough engine idling
• Reduced fuel efficiency
• Excessively lean exhaust
• Other control codes can be stored

What are some of the common causes for the code?

Reasons for this P042E code may include:

• Defective exhaust gas recirculation valve
• Exhaust gas recirculation valve plunger clogged with carbon deposits or other debris
• EGR solenoid / valve defective
• Open or short circuit in the wiring / connectors in the EGR control circuit A
• Defective DPFE sensor
• Defective EGR valve position sensor
• Faulty PCM or PCM programming error

What are some of the P042E troubleshooting steps?

A diagnostic scanner, digital volt / ohmmeter, and a reliable source of vehicle information are among the tools required to diagnose the P042E code.

A visual inspection of all EGR wiring and connectors is the perfect harbinger of a P042E 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 P042E 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. If the actual position of the EGR system indicates that it is too far open, it can be assumed that some soot has clogged the plunger bore or that the EGR valve is faulty.

Obviously, the easiest method to check the EGR plunger is to remove the valve and look. Unfortunately, the location of the EGR valve on some models makes removing (and reinstalling) the EGR valve less than convenient. If the EGR valve can be easily removed for inspection, that would be my first step (especially if the vehicle in question has over 100 miles). Carbon pollution and clogged passages are fairly common problems for high mileage vehicles. If the plunger appears to be damaged, remove the obstruction and recheck the EGR system.

If no obstruction is found in the EGR valve plug bore, 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 the exhaust gas recirculation system for this vehicle uses an EGR valve position sensor, it is probably built into the valve itself. Follow the manufacturer's recommendations and the connector pinouts and vehicle wiring diagrams found in your vehicle information source to check individual components. Replace defective parts 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.

• Carbon deposits are caused by the high detergent content of modern fuels.
• After repairs have been completed, let the PCM go into readiness mode before assuming they were successful.

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• Characteristics of the Suzuki Forenza P2008E 042 engineI get the code P042e on a 2008 Suzuki Forenza. When cel is turned on, there is a noticeable change in engine performance. The EGR valve is ok, I tried the second valve and got the same result. Ignition coil, spark plugs, wires and O2 sensors are OK. My question is: why does CEL light up ... 
• 2008 Suzuki Forenza Delayed CEL P042ESuzuki Forenza, 2008. Sporadic CELs keep popping up, usually somewhere between 30-75 miles after reset. The code reads as P042e. The car drives hard, is quiet, doesn't use fuel - BUT it doesn't splatter, except at startup, after which it runs quite smoothly. New: EGR valve, o2 sensors, spark plugs, wires, coil. Two lines... 

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