P07B8

Code

Generic P — Powertrain

Transmission Park Position Sensor/Switch B Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 28 EN: 42 RU: 20

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Scan for stored and pending DTCs and view freeze frame and live data for park switch inputs
Visually inspect connectors and wiring at transmission range/park switch and at PCM/TCM
Backprobe the park switch B signal, reference and ground with key ON to observe voltage
Check continuity and resistance of signal wire from switch to PCM/TCM (key off)
Wiggle harness and move shifter while watching live data to reproduce fault
Inspect for water, corrosion, damaged insulation, or rodent damage along harness

Reference voltage to switch: typically 5 V (some systems use ignition 12 V) — verify OEM spec
Signal voltage: toggles between ~0 V (ground) and reference voltage when switch changes position
Open circuit: infinite resistance or no continuity between switch signal pin and module
Closed contact: very low resistance (near 0 Ω) between switch terminal and ground or switched terminal per OEM
Expected signal states: Park = specific logic level indicated in OEM data (use scan tool to confirm)

Read and record all DTCs, freeze frame, and live data. Note whether code is current, intermittent, or pending.
Confirm vehicle symptom (no crank, shift issues). Ensure battery is charged and ignition is stable.
Visually inspect connector at park/range switch and PCM/TCM for corrosion, bent pins, moisture, or damage.
Backprobe the park switch B connector with key ON (engine off). Verify reference voltage and ground are present per OEM specification.
Operate the shifter through positions while monitoring the switch B signal on a scan tool or multimeter. Look for expected change of state. If no signal change, suspect switch or wiring.
With ignition OFF, disconnect the switch and check continuity/resistance between switch signal terminal and PCM/TCM terminal. Repair any open circuits.
If wiring is intact, check switch resistance or operation per service manual. Replace the park position switch if it fails to change contacts or shows open internally.
Repair any damaged wiring, terminals, or grounds. Use proper crimping/soldering and seal connectors to prevent future corrosion.
Clear codes, perform functional test and road test to confirm repair. Re-scan to ensure the code does not return.
If wiring and switch verify good and code persists, consider bench-testing or replacing the PCM/TCM and follow manufacturer procedures before module replacement.