P07B9

Code

Generic P — Powertrain

Transmission Park Position Sensor/Switch B Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 55 RU: 37

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Malfunction Indicator Lamp (MIL) illuminated
Starter may be disabled — vehicle will not crank or start unless in Park/Neutral
Gear position indicator may read incorrectly or intermittently
Transmission may enter limp/limited functionality
Intermittent no-start or unexpected starting behavior
Shift interlock (park-to-gear) problems

Read and record freeze frame and live data for park/shift position circuits with a scan tool
Verify other related transmission DTCs or communication errors are not present
Visually inspect wiring harness and connectors at the transmission and PCM for damage or corrosion
Backprobe the sensor connector and measure signal, reference and ground voltages with ignition on
Check continuity between sensor ground and chassis/PCM ground
Perform wiggle test while monitoring signal to reproduce fault

Typical reference voltage (if used): ~5 V (vehicle dependent)
Expected signal: switches between low and high (usually near 0 V = low, ~4–5 V = high) depending on gear
Fault condition: signal stuck low (approximately 0–0.5 V) or shorted to ground
Open circuit may show floating voltage or no reference; short to battery would show near reference voltage

Retrieve freeze-frame data, note conditions when the fault set (ignition key position, gear, temp).
Inspect connectors and wiring at the transmission park switch and PCM for corrosion, bent pins, or damage.
With ignition ON (engine off), backprobe the park B signal terminal. Verify reference voltage, signal level and ground. Compare to expected values.
If signal reads low, check continuity between the signal pin and PCM input pin. Repair any open or high-resistance sections.
Check for shorts to ground: disconnect the park switch connector and measure signal pin to chassis ground; if still low/shorted, fault is wiring or PCM.
If wiring checks normal, bench-test or replace the park position switch / transmission range sensor (B) per manufacturer procedure.
After repairs, clear DTCs, perform functional test (move shifter through positions, verify signal transitions) and confirm code does not return.
If problem persists after wiring and sensor replacement, test or replace PCM only after verifying all other causes exhausted.