P2507 OBD-II Trouble Code: System Too Rich (Bank 1)

P2507 code definition

ECM/PCM Power Input Signal Low

What the P2507 code means

P2507 is an OBD-II generic code for the engine control module (ECM) detecting the power input to the ECM is below the required voltage for the 5 volt internal ECM reference signal voltage to the sensors.

What causes the P2507 code?

• The engine control module (ECM) is detecting that the internal ECM reference voltage of 5 volts has gone below the 5 volts for a specified amount of time.

• A key on condition with the main engine battery falling below 5 volts can generate the fault code.

• The ECM may have an internal failure of the reference 5 volts generator.

What are the symptoms of the P2507 code?

• The Check Engine Light will be illuminated and the code is set in ECM memory as a fault.

• The vehicle may not start if the main battery is below 5 volts.

• The OBD-II scanner port may not be able to access the ECM if the main battery is too low.

• The ECM may have failed internally and cannot produce a signal reference 5 volts.

How does a mechanic diagnose the P2507 code?

• Scans for codes and documents the code in the ECM then looks at the freeze frame data for failure

• Checks the main battery to make sure it has a full charge

• Checks battery connection to properly power the vehicle

• Scans the ECM and looks at the reference voltage to all the sensors to see if it is at 5 volts. If it is, then they will clear the codes and see if the code returns

• Checks the ECM connector and wiring for corrosion causing a low ECM battery input voltage

Common mistakes when diagnosing the P2507 code?

• Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired.

• Failing to clear the ECM codes after the codes are fixed.

• Replacing the ECM for the code P2507 when the code cannot be verified. The code may have been from a main battery falling below the 5 volts.

How serious is the P2507 code?

Code P2507 is an indication that the ECM cannot or has not been able to produce the 5 volt reference voltage needed for all the computer sensors. A failed ECM will result in a no start condition.

What repairs can fix the P2507 code?

• Replacing the engine main battery that has failed
• Clearing the codes and verifying the ECM can produce the 5 volt reference signal voltages
• Repairing the wiring harness to the battery or ECM for power supply to the ECM
• Replacing an ECM with a failure internally of the reference voltage generator

Additional comments for consideration regarding the P2507 code

Code P2507 is for the ECM not being able to produce a 5 volt reference signal to all the sensors. The most common causes to this is the main vehicle battery running below 5 volts and the ignition key is in the “On” position. The ECM would not be able to maintain the 5 volt reference when the battery fell below 5 volts.

Need help with a P2507 code?

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