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Diagnostic trouble code

P166B

P166B Fault Code

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Car Codes diagnostic trouble code

P166BDiagnostic priority

…0/10R80-MHT automatic transmission and built on or before 29-Oct-2020 may exhibit an illuminated malfunction indicator lamp (MIL) and diagnostic trouble codes (DTCs) U0100, U0155, P166B, P0929, and/or P0919. The vehicle may also exhibit an illuminated powertrain malfunction (wrench) indicator lamp. This may be due to the software in the gear shift module (GSM). To correct the condition, reprogram the GSM using the latest software level of th…

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Code interpretation

What P166B means

This code indicates Vehicle fault code with verified manufacturer evidence Its precise meaning depends on the reporting control module, complete failure-type suffix, model year, powertrain and software level.

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Driver experience

Symptoms you may notice

A stored diagnostic trouble code or a related system warning.

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Test, do not guess

Possible causes

The precise cause depends on the reporting module, vehicle specification, circuit condition and software level.

Evidence-led checks

Recommended diagnostic route

Save the complete scan and confirm the code against model-specific technical information before testing.

  1. Capture the evidenceSave the complete all-module scan, code suffixes and freeze-frame data.
  2. Prove the basicsTest battery condition, system voltage, power and grounds.
  3. Identify the reporterConfirm the module that logged the code and check circuit integrity.
  4. Compare live dataReview commanded and actual values under the conditions that set the code.
  5. Test before replacingUse model-specific wiring diagrams, pin tests and technical information.
  6. Verify the repairClear the code only after recording evidence, then confirm it does not return.

Vehicle fitment

Vehicle applicability

Ford Explorer

Before clearing

Can the code be cleared?

Clearing a code without fixing the cause removes useful evidence and may only switch the warning off temporarily. Save the full scan first; a permanent or repeatedly returning code needs testing.

A DTC is evidence, not a parts order.

Confirm the suffix, reporting module, model, year, engine and live data before replacing a component.

Verified public evidence

Manufacturer and model coverage

4 public manufacturer records match this search. These records support applicability research but do not replace VIN-specific workshop information.

P166BFord Explorer
EXPLORER · 2025 · Powertrain

Some 2025 Explorer vehicles built on or before 27-Nov-2024 may exhibit driver power door lock and auto start stop system inoperative with diagnostic trouble code (DTC) P166B in the gear…

Source
P166BFord Explorer
EXPLORER · 2020 · Powertrain

…0/10R80-MHT automatic transmission and built on or before 29-Oct-2020 may exhibit an illuminated malfunction indicator lamp (MIL) and diagnostic trouble codes (DTCs) U0100, U0155, P166B, P0929, and/or P0919. The vehicle…

Source
P166BFord Explorer
EXPLORER · 2021 · Powertrain

…0/10R80-MHT automatic transmission and built on or before 29-Oct-2020 may exhibit an illuminated malfunction indicator lamp (MIL) and diagnostic trouble codes (DTCs) U0100, U0155, P166B, P0929, and/or P0919. The vehicle…

Source
P166BFord Explorer
EXPLORER · 2020 · Powertrain

Some 2020 Explorer vehicles may exhibit an illuminated malfunction indicator lamp (MIL) and diagnostic trouble codes (DTCs) U0100, U0155, P166B, P0929, and/or P0919. The vehicle may also exhibit an illuminated…

Source