P081A Starter Disable Circuit Low Trouble Code

P081A Starter Disable Circuit Low Trouble Code

P081A Starter Disable Circuit Low

OBD-II Trouble Code Technical Description

Starter Disable Circuit Low

What does that mean?

This diagnostic trouble code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Subaru, BMW, Mazda, Volkswagen, Audi, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.


 

If your vehicle has stored a code P081A, it means that the powertrain control module (PCM) has detected a degree of voltage that is higher than expected in the starter disable switch circuit. This type of code may be applicable to vehicles with manual or automatic transmissions.

The starter disable switch is usually a single circuit, open/closed switch which interrupts voltage between the ignition switch and the starter solenoid if the clutch is not depressed, the transmission (manual) is not in neutral, or the transmission (automatic) is not in park. Vehicle applications with an automatic transmission may have the starter disable switch integrated into the neutral safety switch or shift selector switch. The transmission control module (TCM) or the PCM monitor starter disable circuit voltage with the ignition in the ON position. The TCM may be a stand alone module or part of the PCM.

If the PCM detects that starter disable switch circuit voltage is not within allowable parameters, a code P081A may be stored and a malfunction indicator lamp (MIL) illuminated. Multiple ignition cycles (with a failure) may be required for MIL illumination.


What is the severity of this DTC?

A stored code P081A could be accompanied by a no-start condition and also indicates that either an electrical issue or a mechanical failure has occurred. Conditions which contributed to a code of this nature being stored should be rectified as quickly as possible.

What are some of the symptoms of the code?

Symptoms of a P081A trouble code may include:

Engine will not start Engine starts with the transmission in gear No symptoms may be exhibited

What are some of the common causes of the code?

Causes for this code may include:

Defective starter disable switch Shorted or open wiring or connectors in starter disable switch circuit Faulty PCM or a programming error

What are some P081A troubleshooting steps?

A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle specific diagnostic information will be required to diagnose a code P081A.

You may use your source of vehicle information to locate a technical service bulletin (TSB) that matches the vehicle year, make, and model; as well as the engine size, code/s stored, and symptoms exhibited. If you find one, it could yield helpful diagnostic information.

Use the scanner (connected to the vehicle diagnostic connector) to retrieve all stored codes and pertinent freeze frame data. It is a good idea to write this information down before clearing the codes then test-drive the vehicle until the PCM either enters readiness mode or the code is reset.

If the PCM enters readiness mode at this time, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions which contributed to the code being stored may need to worsen before an accurate diagnosis can be made.

If the code is immediately reset, the next step of your diagnosis will require that you search your vehicle information source for diagnostic flow-charts, connector pin-out charts, connector face views, and component testing procedures/specifications.

Step 1

Use the DVOM to test voltage, ground, and signal output at the appropriate starter disable switch. Typical starter disable switch circuits consist of either battery voltage (when activated) or ground (when deactivated).

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