P088B

What it means

P088B is the generic code for a transmission fluid filter that is very deteriorated. The transmission control unit has judged the filter to be badly clogged or at the end of its life, usually from a pressure, flow or calculated service-life monitor. The exact method used to detect this depends on the vehicle and transmission, so only some applications fit this code.

Symptoms

• Transmission warning light or service message on the dashboard
• Harsh, delayed or slipping gear changes
• Transmission overheating or going into limp mode
• Whining or droning noise from the gearbox
• Reduced performance or poor response when accelerating

Possible causes

• Transmission fluid filter clogged with debris or friction material, or past its service lifelikely
• Old, degraded or contaminated transmission fluid that has not been changed to schedulelikely
• Internal transmission wear shedding debris that blocks the filterpossible
• Faulty fluid pressure, differential pressure or temperature sensor giving a false readingpossible
• Wiring or connector fault in the sensor circuit, such as corrosion, chafing or a poor pin fitpossible
• Service interval or filter life counter not reset after a previous filter or fluid servicerare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting transmission temperature, load and speed when the code set, and check for other transmission codes
2. Check for relevant manufacturer service information, bulletins and the service history, including when the fluid and filter were last changed
3. Check the transmission fluid level and condition, looking for a burnt smell, dark colour, metal particles or friction material (the method depends on the transmission type)
4. Inspect the wiring and connectors to any filter pressure or temperature sensor for damage, corrosion or water ingress
5. Use live data to compare fluid pressure and temperature readings against the specification for that transmission
6. Check that the fluid cooler and lines are not blocked and that the transmission is not overheating
7. Drop the pan or inspect the filter if the design allows, and examine the filter and any pan debris to judge internal wear

How to fix

• Replace the transmission fluid filter and refill with the correct specification of fluid
• Carry out a full fluid service to the manufacturer's procedure, then reset the service counter if the vehicle requires it
• Repair or replace any faulty pressure or temperature sensor, or repair damaged wiring and connectors
• Clear or replace a blocked cooler or lines, and rectify the cause of any overheating
• Diagnose and repair the internal transmission fault if heavy debris is found, which may involve overhaul or replacement of the unit

Can I keep driving?

Nearby codes

• P088AGenericTransmission Fluid Filter Deteriorated
• P088CGenericReverse Inhibit Control Circuit Low