Low or degraded transmission fluid, or the wrong fluid type; Worn reverse clutch, band or friction plates causing slip; Low line pressure from a weak pump, blocked filter or internal seal leaks; Faulty solenoid or valve body wear affecting reverse apply pressure; Faulty input or output speed sensor, or damaged wiring and connector giving a false ratio; Torque converter fault or lock-up problem (on automatic models); Outdated transmission control software where the manufacturer has issued a known fix.

P0736

Reverse Incorrect Ratio.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
7: AreaTransmission
36: FaultThe specific fault in that area

What it means

P0736 means the transmission control module has detected that the gear ratio in reverse is not what it expects. It works this out by comparing transmission input speed with output speed while reverse is selected, and the code sets when the calculated ratio is outside the allowed range. This usually points to slipping inside the transmission, but the exact cause depends on the transmission type and model.

Symptoms

Slipping or revving with no matching movement when reverse is selected
Delayed or harsh engagement into reverse
Car will not reverse, or reverses weakly
Gearbox warning light or malfunction indicator lamp on
Transmission may go into a limp or protection mode
Burning smell or dark, burnt-smelling fluid

Possible causes

Low or degraded transmission fluid, or the wrong fluid typelikely
Worn reverse clutch, band or friction plates causing sliplikely
Low line pressure from a weak pump, blocked filter or internal seal leakspossible
Faulty solenoid or valve body wear affecting reverse apply pressurepossible
Faulty input or output speed sensor, or damaged wiring and connector giving a false ratiopossible
Torque converter fault or lock-up problem (on automatic models)rare
Outdated transmission control software where the manufacturer has issued a known fixrare

How to diagnose

Read all stored codes and freeze frame data, noting gear selected, fluid temperature and speeds when the code set
Check for other transmission or speed sensor codes, as these can point to a sensor fault rather than mechanical slip
Check fluid level and condition using the correct procedure for the model, looking for a burnt smell, dark colour or debris
Inspect the transmission wiring, connectors and speed sensors for damage, corrosion, oil contamination or leaks
Use live data to compare input and output speed in reverse and check that the calculated ratio is stable
Check the sensor signals and the solenoid operation and resistance against the manufacturer's specification
Perform a line pressure test where the manufacturer provides a procedure and specification
Check for any manufacturer software updates or technical bulletins for the model and transmission

How to fix

Correct the fluid level and replace degraded fluid with the specified type, and change the filter where the design allows
Repair or replace faulty speed sensors, wiring or connectors
Replace faulty solenoids or repair the valve body as needed
Overhaul or replace the transmission if the reverse clutch or band is worn or pressure loss is internal
Apply an updated transmission control software calibration only if a known fault for that model is confirmed

Can I keep driving?

High severity

Avoid driving until the cause is found, as continued slipping can quickly damage the transmission. If reverse is unreliable, you may not be able to manoeuvre safely, so arrange a recovery or a short, careful trip to a workshop only.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.