P0802 OBD-II Trouble Code: Transmission Control System MIL Request Circuit/Open

P0802 code definition

The malfunction indicator lamp, or MIL, of the automatic transmission control system, is not operating correctly if the P0802 code has been stored in the PCM.

What the P0802 code means

This code is stored when there is a problem with an indicator lamp, which could mean that a variety of actual failures have occurred. If there is an anomaly detected within the automatic transmission control system, it will send a code to the PCM. It will also activate a MIL. If the MIL does not illuminate, then the P0802 code will also be stored in the PCM.

What causes the P0802 code?

This code is only caused by the failure of an indicator lamp to illuminate. This usually means that the indicator lamp bulb is malfunctioning. It may also be caused by faulty wiring or corroded connectors between the MIL and the automatic transmission control system.

What are the symptoms of the P0802 code?

Because the P0802 code could be triggered by a large variety of actual malfunctions, it is hard to say exactly what symptoms will be experienced. In some cases, a small malfunction that does not usually have any symptoms may have prompted the transmission control system to illuminate the MIL, which then failed. However, in some cases, a very large malfunction could have caused the control system to illuminate the MIL. In this case, the symptoms could be as significant as total transmission failure.

The most commonly seen symptoms related to the P0802 code include:

• The lack of a Check Engine Light, even though the car is clearly malfunctioning.
• Transmission slippage or over-heating.
• Difficult shifting or a failure to shift.
• An engine that stalls when stopped.

How does a mechanic diagnose the P0802 code?

If the OBD-II scanner detects the P0802 code, the first step is to inspect all the wiring and connectors that go between the MIL and the automatic transmission control system. If these are in good repair, or have been repaired or replaced, then the code should be cleared and the vehicle should be retested. If the code returns, the technician should move on to other repairs.

Common mistakes when diagnosing the P0802 code

Because this code can result in a Check Engine Light that does not illuminate, it can mean that other stored codes are not checked for and addressed. It’s important to check the PCM for other stored codes if a P0802 code is detected.

How serious is the P0802 code?

The seriousness of the P0802 code depends entirely on the reason the MIL was activated in the first place. Some small issues may not be very serious, while others may be essential repairs to make right away. Your technician will be able to tell you more accurately how serious the issue is once they have diagnosed the true issue behind the P0802.

What repairs can fix the P0802 code?

To repair the specific issue of the MIL that will not illuminate, the repair technician should perform the following:

• Verify the code with a scanner, and repair or replace any faulty wiring or connectors.
• Check for and replace any burnt MIL bulbs.

However, the P0802 code is an informative code that indicates that there was a larger issue at hand. In order to truly repair the root cause of the P0802 code, the mechanic should also check the PCM for other stored codes, and address those issues as well. That may include inspecting and repairing issues with the transmission in a variety of ways.

After each specific repair, the specifically addressed codes in the PCM should be cleared, and the system should be retested. This allows the mechanic to narrow down the issue more quickly. If the transmission issue is addressed, and the MIL bulb and all electrical components have been addressed, then the P0802 code should not reappear.

Need help with a P0802 code?

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