P0002 trouble code definition
The P0002 code is associated with the electrical circuit which connects to your fuel pressure regulator.
It also may be related to other codes, such as: P0001, P0003, or P0004.
What the P0002 code means
P0002 is a generic OBD-II code indicating an issue with the engine control module (ECM) reading signals from your fuel pressure regulator on your fuel injection rail mounted to your engine.
The ECM regulates your fuel pressure from your fuel pump going to your engine through this circuit and receives input on your actual fuel pressure. When the computer detects a pressure it is not commanding to the fuel pump, it will set a Check Engine Light. The code will affect fuel economy and possibly damage the engine. On a side note, this code is rare.
What causes the P0002 code?
The fuel volume regulator range/performance code may have several causes:
- Disconnected plug to the fuel regulator
- Possible corrosion in the sensor connector
- Damage to the sensor wiring to the ECM
- Leaking or defective fuel pressure regulator
- Damaged fuel pump
- The ECM is damaged
What are the symptoms of the P0002 code?
The P0002 code will produce a Check Engine Light on the instrument panel/dash and will likely affect:
- Your engine performance during driving
- Possible stalling while driving
- It may cause the exhaust to show black or white smoke
- Fuel economy will be affected
- Damage to the catalytic converter in your exhaust
How does a mechanic diagnose the P0002 code?
P0002 is properly diagnosed with an advanced scan tool capable of factory sensor readings (not just one from an auto parts store). A qualified technician can read the data from the advanced scan tool to determine when the problem occurred, or if it is still occurring. They may clear the code/light and test drive the vehicle while monitoring the scan tool data to see if the fault returns or is present.
Based upon the conditions of the test, possibly clearing the code, and road testing the car while monitoring the data, further diagnosis may be required. Diagnosis may require multiple tools such as:
- An advanced scan tool to read the ECM data values
- A digital voltage meter with attachments
- A fuel pressure tester
Common mistakes when diagnosing the P0002 code?
Just replacing the fuel pressure regulator never guarantees a successful repair in resolving your issue. It may be caused by several components in the fuel system as listed above and more. A visual inspection and testing with special equipment listed above will verify your issue before unnecessarily spending money and time replacing the fuel pressure regulator.
Electrical signals require evaluation by an advanced scan tool, a voltage meter, and a fuel pressure tester to ensure that the fuel pressure regulator requires replacement or if another problem exists. Additional testing may be required.
How serious is the P0002 code?
The P0002 fault code could cause your vehicle from running and will:
- Affect fuel economy
- Cause fuel instability which may cause damage to your engine
- Potentially damage your catalytic converters (which is an expensive repair)
- Prevent your vehicle from passing emissions
A qualified technician can diagnose the problem with proper tools to verify these potential issues.
What repairs can fix the P0002 code?
The most common procedure to repair the P0002 code are as follows:
Connect a professional scan tool. Verify the code exists.
Check for any other fault codes. Clear the fault codes to see which codes return.
Analyze scan tool data from the ECM.
Road test the vehicle while analyzing the scan tool data from the ECM.
Check to see if the P0002 code returns.
Inspect all of the items listed above. (wiring, leaks, pressures, voltages, etc)
Further diagnose the problem with the equipment listed above if the problem appears to be present. The signals from the sensor need to be analyzed to determine where the problem exists. If the signals are fine, then we need to move towards the wiring, computer, or fuel system.
Additional comments for consideration regarding the P0002 code
Any sensor issue may occur all the time or intermittently. Some fault codes will require additional time to diagnose. With this particular code, the solution may be something simple to replace or require extensive time to diagnose and repair. Depending on your vehicle, it may take several hours to determine the root cause and repair the faulty component.
I have rarely experienced this code in the past which makes me believe it would require extensive diagnosis. After using a scan tool and monitoring the voltage, I could determine if the fuel pressure regulator, wiring, ECM, or fuel pump is at fault. With the scan tool connected I typically evaluate the data while checking the fuel pressure and using a voltage meter to ensure all the values are adequate and match specifications. If the values do not match, then a further diagnosis is required.
The sensor may be the cause, wiring issues might be burning/rubbing on another engine component, rodents may have chewed through wiring anywhere in the vehicle, connectors may have corrosion or damage, the fuel system may have a fault, or you may have a bad ECM.
An advanced scan tool with specialty tools inspection is required. Then we will determine where the fault lies. We may clear the fault code/light first, then verify if the Check Engine Light returns, and diagnose from there. It may have been a weird occurrence from bad gas or weather, or it may be permanent problem.
Vehicles with high mileage (over 80,000 miles) may just need a fuel pressure regulator replacement. However, replacing parts based upon a code is not recommended and has caused problems or not resolved the issue.
Need help with a P0002 code?
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This article originally appeared on YourMechanic.com as P0002 OBD-II Trouble Code: Fuel Volume Regulator Control Circuit Range/Performance and was authored by Paul Lancette.