P2800

Code

Generic P — Powertrain

Transmission Range Sensor B Circuit (PRNDL Input)

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 42 RU: 34

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Page language: EN

Causes

Open or short in the PRNDL sensor B wiring (to ground or battery)
Corroded, loose or damaged connector at the range sensor or PCM/TCM
Faulty transmission range (park/neutral) sensor or internal resistance ladder failure
Poor chassis or sensor ground
Blown fuse or power supply interruption to the sensor circuit
Water intrusion or contamination at the sensor/connector

Symptoms

MIL (Check Engine Light) illuminated
Gear selector indicator may display incorrectly or not change
Vehicle may fail to start except in Park/Neutral or exhibit no-crank in gear
Transmission may enter limp/safe mode with limited gears
Intermittent starting or shifting problems
Stored related transmission codes or driveability faults

What to check

Read and record freeze frame and all stored DTCs; note occurrence conditions
Visually inspect range sensor connector and PCM/TCM connector for corrosion, bent pins or water
Check related fuses and power supplies for the transmission/PRNDL circuit
Check battery voltage and main grounds for good connection
Backprobe the PRNDL B signal and ground with key ON and while shifting through positions
Wiggle test wiring and observe for intermittent change in signal or codes

Signal parameters

PRNDL B is typically a variable voltage signal referenced to PCM/TCM reference (0–5 V range)
Expected voltage will change by gear position (distinct voltages for P, R, N, D, etc.)
Open circuit: signal may read near 0 V (or high impedance); short to ground: ~0 V
Short to battery: signal may read ~12 V (or stuck near reference/battery)
Intermittent or out-of-range voltages indicate wiring, connector, or sensor faults

Diagnostic algorithm

Verify code with scan tool, note freeze frame and whether code is current or historic; clear code and attempt to reproduce.
Perform visual inspection of wiring and connectors at the transmission range sensor and PCM/TCM. Repair obvious damage and re-test.
Check fuses and power/ground circuits for the transmission module and range sensor. Repair as needed.
Backprobe PRNDL B signal at the sensor with key ON (engine OFF). Record voltage in each gear position while an assistant moves the shifter. Compare to expected distinct voltage steps.
If signal is missing or fixed at an abnormal voltage, check for continuity between the sensor signal pin and the PCM pin. Check for short to ground or battery with an ohmmeter (ignition OFF).
Wiggle harness and connectors while monitoring signal for intermittent faults. Repair broken wires, pins, or corrosion.
If wiring and connectors check good, test or replace the transmission range sensor and re-test.
If new sensor and harness correct the issue but code persists, inspect PCM/TCM connector and re-program or replace module only after confirming module-level fault.
After repairs, clear codes and perform a road/test cycle and re-scan to verify the fault does not return.

Likely causes

Damaged or corroded connector/wiring between range sensor and PCM/TCM
Open circuit or short to ground in sensor B signal wire
Faulty transmission range (PRNDL) sensor

Fault status

⚠️ Status

Transmission Range Sensor B Circuit malfunction (PRNDL input). PCM/TCM detected invalid or out-of-range voltage on PRNDL-B. May set MIL, affect starting in gear, or trigger limp mode.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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