OBD-II Code P0733 — What It Means & How to Fix It

What Does This Error Mean?

P0733 means the TCM has detected an incorrect gear ratio when 3rd gear is engaged. This is most often caused by a slipping 3rd-gear clutch pack but can also be a faulty solenoid or speed sensor. Driving with the underlying issue unresolved typically worsens internal wear.

Affected Models

All vehicles 1996+ with automatic transmissions
Common in GM 4L60E and 6L80
Common in Ford 4R70W, 5R55, and 6R80
Common in Chrysler 8HP and 42RLE

Common Causes

Slipping 3rd gear clutch pack
Failed 3rd-gear shift solenoid
Worn input or output speed sensor producing wrong ratio calculation
Low transmission fluid level or pressure
Worn valve body causing pressure loss in 3rd

How to Fix It

Service the transmission fluid first.

Low or degraded fluid is a common root cause and the cheapest fix. A fresh service often clears P0733 if no internal damage is present.
Pull all stored codes.

Companion solenoid codes (P0760, P0761) point to electrical issues; companion speed sensor codes point to feedback issues. Investigate them before assuming clutch wear.
Test speed sensor outputs.

Confirm input and output speed sensors produce healthy signals. A weak sensor causes apparent ratio errors that disappear after the sensor is replaced.
Check for TCM software updates.

Some manufacturers issue TCM reflashes that resolve early-fault detection issues. A dealer scan of your VIN catches any applicable updates.
Book a transmission shop for line pressure testing.

If fluid, codes, sensors, and software are all clean, line pressure testing identifies hydraulic vs mechanical failure. This guides repair scope.

When to Call a Professional

P0733 typically requires shop diagnosis with a line pressure test. Fluid and solenoid repair costs USD 250–800. Rebuild for clutch pack failure: USD 1,500–3,500. Get at least two estimates before authorising rebuild work.

Frequently Asked Questions

Will P0733 cause my car to fail emissions?

Some states fail vehicles for any active P-code with the check engine light on. P0733 is a transmission code (not directly emissions related) but the check engine light alone is grounds for failure in many regions. Clear and resolve before emissions testing.

Can a fluid flush fix P0733?

Sometimes — if the issue is a fluid pressure problem from old or contaminated fluid, a service often clears the code. If the cause is mechanical wear or a failed solenoid, a flush will not help. Start with the cheapest options first.