U0588 Moderate Generic / SAE

U0588: Invalid Data Received From Transmission Fluid Pump Module A

Network and Communication Invalid Data Received (continued)

What to do

The car drives normally. The most likely sign is that stop-start has quietly stopped switching the engine off at junctions.

That is deliberate rather than broken. The car will not stop the engine when it cannot be sure of holding transmission pressure through the stop — so what you are seeing is a protection, not a failure.

Worth repairing rather than living with, particularly on a hybrid, where the same pump covers every engine-off moment and a shunt at each restart is wear the clutches were not designed for.

If gear changes have also become harsh, or there is a pause before the car moves off, say so — that moves the diagnosis from the electrical side to the hydraulic one, and there are separate codes covering that.

What this code means

Transmission fluid pump module A is broadcasting data that cannot be accepted as true. See U0400 for what an invalid-data code is and why the module it names is usually the messenger rather than the culprit.

This is the electric auxiliary transmission fluid pump, and the corpus already documents its faults in depth in the P27xx range — this code is the network's view of the same part.

The pump exists for the moments the engine is off. A conventional automatic makes its hydraulic pressure from an engine-driven pump, so at a stop-start red light the pressure would fade and the first metre of drive would arrive with a thump. The electric pump holds pressure through those stops, and hybrids lean on it whenever the engine sleeps.

What this code adds to the P27xx family is the direction of the fault. A pressure or control code at P2796 onward describes the pump misbehaving; this describes the pump's module publishing data the network will not accept, which points more at the reporting path than the hydraulics — connectors, the module's own supply, or a software mismatch after work.

The symptom is the same either way, and it is a quiet one: stop-start giving up. The module will not permit an engine stop it cannot cover, so a car that used to switch off at the lights and no longer does, with this stored, has already explained itself.

See P27E1 and P2796 for the hydraulic side, which is where the mechanical diagnosis belongs.

Likely causes

Start here

Corroded or loose connector · specialist
Damaged data bus wiring · moderate

Less common

Water ingress into module · moderate
Software updated on one module only · specialist
Failed power or earth supply to the module · specialist
Low or degraded transmission fluid · moderate

Symptoms

Components involved

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

Community experience

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