U0516 — Invalid Data Received From Door Switch

Generic OBD-II · all makesNetwork / communication

U0516 indicates that the Powertrain Control Module (PCM) has detected invalid or out‑of‑range data from one of the door switch circuits. This typically means the signal from a door ajar switch is missing, intermittent, or corrupted.

Symptoms

Dashboard illumination of a door‑ajar warning light without any door actually open
Intermittent or permanent “door open” message on the instrument cluster
Exterior lights (e.g., courtesy lights) failing to operate correctly when doors are opened or closed
Reduced interior lighting or delayed activation of interior lamps
In some cases, the vehicle may prevent starting if the PCM interprets a door‑open condition as a safety fault

What causes it — most likely first

1. Faulty door ajar switch or wiring

The most common cause is a defective door switch, a broken wire, or a poor connector that sends corrupted signals to the PCM.

2. Corroded or loose connector at the door switch

Moisture, dirt, or vibration can loosen the connector pins, creating intermittent or invalid data.

3. Shorted or open circuit in the door‑switch harness

A short to ground or an open circuit anywhere in the harness can produce out‑of‑range voltage levels that the PCM flags as invalid.

4. PCM input pin failure or internal fault

Rarely, the PCM’s input circuitry for the door‑switch signal can fail, causing it to read invalid data even though the switch and wiring are good.

How it's diagnosed

Visually inspect all door‑switch connectors and wiring for corrosion, damage, or loose pins.
Use a multimeter to verify the continuity of the door‑switch harness from the switch to the PCM connector.
Measure the voltage or resistance at the door‑switch sensor while opening and closing the door to confirm proper operation.
If the switch and wiring test within specifications, scan the PCM for additional communication or input‑module faults.
As a last step, perform a PCM input‑pin test (if service information is available) or replace the PCM only after ruling out all external faults.

Code facts & related codes

SystemNetwork / communication

StandardizationSAE generic — identical on every make

Frequently asked

Can the PCM be the cause of a U0516 code?

It is possible but uncommon. The PCM is usually reliable; most U0516 codes are traced to a bad door switch, wiring, or connector.

Should I replace the door switch immediately?

Only replace the switch after confirming it is defective with a voltage or resistance test. A visual inspection alone is not enough.

Why do some technicians suggest swapping the PCM for this code?

That advice is often based on a misunderstanding. Replacing the PCM is expensive and rarely resolves U0516; it should be considered only after exhaustive testing of the switch, wiring, and connectors.

Will fixing the door‑switch issue clear the code automatically?

After repairing the faulty component, clear the codes with a scan tool and verify that the code does not return on a drive cycle.