Transmission

P1701 — Reverse Gear Incorrect Ratio

Severity: medium Drive with care, to a shop

What P1701 means

The transmission control module compares input and output shaft speeds in reverse against the expected ratio. If they do not match, it sets P1701, which usually points to a slipping clutch or band or too little hydraulic pressure in the reverse circuit. The definition varies by manufacturer, so check the details for your brand.

Symptoms

  • Slipping in reverse
  • Delayed reverse engagement
  • Harsh or jerky engagement into R
  • Transmission or check engine light on
  • Weak backing up on an incline
  • Transmission enters limp mode

Possible causes

  1. Low ATF level
  2. Dirty or worn-out fluid
  3. Worn reverse clutch pack
  4. Worn or failed reverse band
  5. Clogged filter or low line pressure
  6. Faulty solenoid or valve body
  7. Leaking reverse piston seals

How to diagnose

  1. Scan all codes and freeze frame data and look for other transmission codes
  2. Check ATF level and condition per the manufacturer's procedure: color, smell, debris
  3. Inspect for fluid leaks and fix any found
  4. Check for service bulletins and TCM software updates
  5. Measure line pressure in the reverse circuit
  6. Test solenoids and wiring for opens and shorts to ground
  7. Drop the pan and inspect the filter and sediment for friction material
  8. If needed, open the transmission and inspect the clutches and band

Common fixes

  • Top off or replace ATF and filter
  • Repair the fluid leak
  • Replace a solenoid or repair the valve body
  • Repair wiring or connectors
  • Update TCM software
  • Rebuild the transmission with new reverse clutches and band

P1701 on different brands

Chevrolet · manuals
On Chevrolet this code is listed as a Transmission MIL Request circuit fault.
Ford · manuals
On Ford it is described as a reverse engagement error condition.
Hyundai · manuals
On Hyundai the source ties it to the throttle position sensor (TPS) circuit, so check that sensor.
Land Rover
On Land Rover it indicates a transfer box fault signal.
Mercedes-Benz · manuals
On Mercedes-Benz it means an electrical fault in the transmission shift control valve.
PSA
On PSA it is a control unit fault in the MCP 6-speed piloted manual gearbox (Peugeot, also Citroën), related to gear changing control.
Subaru · manuals
On Subaru it refers to a malfunction in the cruise control set signal circuit for the automatic transmission.
Suzuki · manuals
On Suzuki it means a CAN bus communication fault with the transmission control module (TCM).

Questions and answers

What does P1701 mean?

Generally it means an incorrect gear ratio in reverse, caused by slip or low hydraulic pressure. Some brands use the code for a different specific fault.

Can I drive with P1701?

Briefly and carefully, after checking the fluid. If the transmission is slipping, driving on will speed up wear.

Will adding fluid fix it?

If low fluid is the cause, it can. You still need to find why it was low, and if the clutches are already worn, the transmission needs repair.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.