P07B4 Park position sensor or switch circuit reading high

Transmission park position sensor/switch A circuit high

P07B4 in short

P07B4 means the transmission computer saw the park position sensor or switch circuit reading higher than expected. On GM trucks and the XT5 it often comes with a Service Transmission warning. Causes include the shifter assembly or its connection and wiring. Have it inspected soon, and stop if the vehicle will not shift.

Many newer cars use electronic shifters, and the transmission computer reads the shifter and park position electrically. P07B4 is set when the park position sensor or switch circuit voltage is higher than the computer expects.

On GM trucks, owners report the code with a Service Transmission Now or Unable to Shift Soon message. One dealer found the wiring good and followed GM service information to replace the gear shift control module, and a Silverado owner reports the shift control assembly on backorder for weeks. GM also has a customer satisfaction program on the 2017 Cadillac XT5 where a shift knob that comes loose breaks the electrical connection and sets P07B4 with several other codes.

A Dodge Dart owner was told P07B4 was a park positioning sensor code. Different makes may use the same code for a different part, so the shifter and sensor are where to start.

Most likely causes

  1. Gear shift control assembly or module

    Supported by vehicle data
    Why it ranks here
    GM trucks with P07B4 had the shift control assembly or module replaced or ordered, and the dealer followed service information in one case. Complaint data only.
    What would change this
    Rises if wiring tests good and the shifter message appears. Falls if wiring or connector damage is found.

  2. Loose or broken shift knob electrical connection (XT5)

    Supported by vehicle data
    Why it ranks here
    GM GCUS-3-631 says a detached knob breaks the electrical connection and sets P07B4 with other codes on the 2017 XT5; dealers inspect the knob and clear codes. A 2020 XT5 owner reports a fractured shifter piece with P07B4.
    What would change this
    Rises on an XT5 with a loose or cracked knob or shifter. Falls on other vehicles or if the knob is firmly fitted.

  3. Park position sensor, switch or wiring

    Possible — needs testing
    Why it ranks here
    TroubleCodes.net describes the code as a circuit high on the park position sensor or switch, so a sensor, wiring or connector fault is plausible, but no source we read confirmed a specific repair.
    What would change this
    Rises if a circuit test finds a short to voltage or poor connection. Falls if the circuit tests good.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all codes. Note P07BA, P17A4, P17A8 and U156D if they are stored with P07B4.

    Low riskTool: scan tool that reads the transmission module

  2. Have the wiring and connector between the shifter and the control module tested.

    Best left to a shopTool: multimeter, scan tool

    Warning:The shifter area has airbag and other safety wiring nearby. Leave this to a shop.

Symptoms

  • Check engine light, sometimes flashing
  • Service Transmission or Service Transmission Now message
  • Gear Conditions not Met message
  • Unable to Shift Soon, or the vehicle will not shift Gets more serious: stop and have it checked.

How to fix

Parts and cost context

  • Transmission control module (TCM):The shifter assembly, not the transmission computer, is what the GM reports replaced. Parts availability has been slow in complaints. Labor varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

GMC

  • 2022–2023 · Sierra 1500

    Supported by vehicle data

    Dealers read P07B4 with a Transmission Service warning; one followed service information to replace the gear shift control module.

Chevrolet

  • 2022 · Silverado 1500

    Supported by vehicle data

    An owner reports Service Transmission Now / Unable to Shift Soon with P07B4 and a shift control assembly on backorder.

Cadillac

  • 2017–2020 · XT5

    Supported by vehicle data

    GM GCUS-3-631 covers a detached shift knob that sets P07B4 and other codes; a 2020 owner reports a fractured shifter piece.

  • GCUS-3-631Status unverified

    Shift knob may detach; Service Transmission message and DTCs including P07B4

    2017xt5 · NHTSA 10135432

    Dealers are to inspect and verify the shift knob is installed correctly and clear all DTCs.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Dodge

No curated relationships for P07B4 yet.

All Transmission codes

P07B4 questions

Can I still drive with P07B4?

Only if the vehicle selects gears normally. If it shows Unable to Shift Soon or will not shift, stop driving and have it checked.

Sources and review

  1. GM GCUS-3-631: shift knob detached, Service Transmission message and DTCs including P07B4 (2017 XT5) — Gm (filed with NHTSA)
  2. NHTSA complaint ODI 11769411: 2022 Chevrolet Silverado 1500, P07B4 — NHTSA Office of Defects Investigation (consumer complaint)
  3. P07B4 – Transmission Park Position Sensor/Switch "A" Circuit High — TroubleCodes.net
  4. NHTSA complaint ODI 11742551: 2023 GMC Sierra 1500, P07B4 — NHTSA Office of Defects Investigation (consumer complaint)
  5. NHTSA complaint ODI 11721495: 2020 Cadillac XT5, P07B4 P07BA P17A4 P17A8 — NHTSA Office of Defects Investigation (consumer complaint)
  6. NHTSA complaint ODI 11422166: 2013 Dodge Dart, P07B4 — NHTSA Office of Defects Investigation (consumer complaint)
  7. NHTSA complaint ODI 11715584: 2022 GMC Sierra 1500, P07B4 — NHTSA Office of Defects Investigation (consumer complaint)
Last reviewed
Written by
Saurabh K.
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