HomeTrouble CodesP2802

P2802 — Transmission Range Sensor B Circuit Low

Manufacturer-specificPowertrain (engine & transmission)

P2802 means the Powertrain Control Module (PCM) has detected a low voltage condition on the Transmission Range Sensor B circuit. This sensor tells the PCM which gear the transmission is selected in, so a low signal can cause incorrect gear recognition and shifting issues.

Symptoms

What causes it — most likely first

1. Failed Transmission Range Sensor B

The sensor itself can develop an internal short or open circuit, pulling the signal voltage low and triggering the code.

2. Wiring short to ground or damaged harness

Chafed, pinched, or corroded wires in the sensor circuit can create a low‑resistance path to ground, causing the PCM to read a low voltage.

3. Loose or corroded connector at sensor or PCM

Poor contact in the sensor plug or the PCM harness connector can increase resistance and produce a low signal reading.

4. Blown fuse or power supply issue for the sensor circuit

If the fuse supplying voltage to the range sensor circuit is open, the sensor may receive insufficient voltage, appearing as a low signal.

5. PCM internal fault (rare)

A malfunction inside the PCM’s input circuit for the sensor can falsely register a low voltage; this is considered only after wiring and sensor checks are normal.

6. Aftermarket modifications or tampering

Non‑standard wiring, added accessories, or previous repairs that altered the sensor circuit can introduce faults leading to a low signal.

How it's diagnosed

  1. Retrieve the code and any related freeze‑frame data to confirm conditions when the fault occurred.
  2. Visually inspect the transmission range sensor B wiring harness and connectors for damage, corrosion, or loose pins.
  3. Measure sensor resistance and output voltage with a multimeter according to the service manual specifications; compare to known good values.
  4. Test continuity and check for shorts to ground in the sensor circuit wiring between the sensor and PCM.
  5. Verify proper power and ground supplies at the sensor connector; check the relevant fuse and relay if applicable.
  6. If sensor, wiring, and power/ground are all within spec, consider testing or replacing the PCM as a last resort.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is replacing the PCM a common fix for P2802?

No. The PCM is rarely the cause; most P2802 cases are due to a faulty sensor, wiring issue, or connector problem. Replacing the PCM should only be considered after those components have been verified good.

Can I drive the vehicle with a P2802 code?

Driving is possible but not recommended. The transmission may default to a limp‑in mode, causing reduced power, harsh shifting, or inability to select certain gears, which can lead to unsafe driving conditions.

Will clearing the code fix the problem?

Clearing the code only turns off the Check Engine Light; if the underlying fault remains, the code will return once the PCM detects the low signal again.