P07FF: Cold Start Transmission Performance

P07FF means the transmission does not work as expected during the cold-start phase, shortly after starting with cold, thick fluid – for example a gear preselection or a clutch or valve response outside the expected window. The only documented user is Mercedes-Benz: its 2024 bulletin for the eight-speed dual-clutch gearbox 8G-DCT in the compact models (A-Class, CLA, GLA, GLB) names P07FF together with P0921, with reverse not available, a possible limp-home mode and the MIL; after switching off and on everything works again, and the fix was new control unit software. No thresholds or trip counts are published. It is not CARB's cold-start emission strategy, which concerns engine and catalyst heating (P050A ff), but a functional check of the transmission.

Symptoms

• Reverse not available (message in the cluster)
• Check engine lamp on
• Limp-home mode shortly after a cold start
• Normal again after switching off and on

Most likely causes

• Transmission control module software misjudging the cold phase
• Shift valve or hydraulics too slow with cold fluid
• Wrong or aged fluid, low level
• Fluid temperature sensor reading wrong

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the fluid level and condition
2. Compare the reading with other engine data while varying the engine speed.
3. Read the input and output speed in live data
4. Check the connector and wiring
5. Check for other related engine codes
6. Consult the manufacturer's procedure for the transmission

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P07FF means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 7: Transmission
• FF: Specific fault in that system

Frequently asked questions

Can I keep driving with code P07FF?

Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.

What causes code P07FF?

The most common causes are: transmission control module software misjudging the cold phase; shift valve or hydraulics too slow with cold fluid; wrong or aged fluid, low level.

Related codes

• P0921Gear Shift Forward Actuator Circuit Range/Performance
• P0700Transmission Control System (MIL Request)
• P0711Transmission Fluid Temperature Sensor A Circuit Range/Performance
• P0712Transmission Fluid Temperature Sensor A Circuit Low
• P0713Transmission Fluid Temperature Sensor A Circuit High

Sources

• static.nhtsa.gov: MC 11008066 0001
• static.nhtsa.gov: MC 11007793 0001
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.