P0948 Generic (SAE) Basic entry

Hydraulic Pump Relay Circuit High

Updated 2026-10-02 · Transmission

Severity

Medium

Typical repair cost

40 – 350 EUR

System

Powertrain

What it means

P0948 is stored when the engine control module measures a voltage in the Hydraulic Pump Relay circuit above the expected maximum, typically because the signal wire is shorted to battery voltage or the circuit is open and pulled up internally.

This entry is compiled automatically from the standard definition and typical diagnostic practice for this type of fault. A detailed, reviewed article is in preparation.

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Symptoms

Check engine or transmission warning light
Harsh, delayed or missing shifts
Transmission stuck in one gear (limp mode)
Shuddering or slipping under load

Common causes

Damaged, chafed or corroded wiring in the Hydraulic Pump Relay circuit
Corroded, loose or water-damaged connector terminals
Failed Hydraulic Pump Relay component (sensor, solenoid or actuator)
Poor ground connection for the module or component
Faulty control module driver (rare, confirm all else first)

How to diagnose

Read freeze frame data and note when the code set (cold start, under load, after rain)
Inspect the Hydraulic Pump Relay connector for bent pins, corrosion and water; wiggle the harness with the engine running and watch live data
Measure supply voltage and ground at the connector with the key on
Check the signal wire for shorts to ground or battery and for continuity to the control module
Test or substitute the Hydraulic Pump Relay only after wiring and connectors are confirmed good
Clear the code and complete a drive cycle to confirm the repair

Frequently asked questions

Can I keep driving with P0948?

Usually yes for a short time, but expect reduced performance or higher fuel use. Have it diagnosed within a few days.

Will clearing P0948 fix it?

No. Clearing only erases the stored code; it returns as soon as the monitor runs again unless the cause is repaired.

Related codes

P0946 P0947 C1936