P0553 means the engine control module saw the power steering pressure (PSP) sensor or switch signal above its maximum acceptable voltage. The family is P0550 (circuit), P0551 (range or performance), P0552 (low), P0553 (high) and P0554 (intermittent). On a three-wire sensor with a pull-up in the module, an open signal wire, an open ground or an unplugged sensor leaves the signal at the reference voltage: high. On a two-wire switch that closes to ground under pressure, a switch that never closes or a broken wire reads the same way.
Severity: low. Can you keep driving? Yes. Steering assist does not depend on this signal. The engine computer uses it to raise idle when the pump loads the engine, so the symptom is a stumble or stall when turning the wheel at idle, with the check engine light on.
Why the engine cares
A hydraulic steering pump at full lock can take several horsepower and stall a small engine at idle. The PSP device warns the computer a moment before, so it can add air or throttle. With the signal stuck high the module either never sees the load or assumes it is always present, depending on the design, and idle control suffers either way.
Causes, in the order they are found
A connector unplugged or backed off, often after belt, pump or alternator work nearby.
A wire broken in the harness near the pump, cut by a shredded belt or fatigued at a tie point.
An open ground on designs that ground the switch through the harness rather than through its threads, or corrosion on a ground eyelet.
A switch whose contacts never close, or a sensor with an open element.
Low pump pressure on switch designs, when the pump cannot reach the pressure the switch needs; usually with a groaning pump and low fluid.
The module, last.
A diagnostic order
- Record the freeze frame and companions. Idle control codes beside it confirm the symptom path.
- Look at the connector. Unplugged or half-seated is the most common finding for this code.
- Check fluid level and listen to the pump.
- For a sensor, key on, plugged in and back-probed: the signal should sit low with the wheel straight and rise as the wheel is turned to a lock at idle. Pinned at the reference regardless of steering means an open ground, an open signal wire or a dead sensor. Unplug and measure the ground pin to battery negative: under 0.1 V of drop.
- For a switch, key on: measure across the switch pins with the wheel turned to a lock, engine running; it should close (or open, per the design). Check continuity of its wire to the module and its ground.
- Wiggle-test the harness near the pump and the belt with the engine running.
- Repair the wire or connector, or replace the device only if it measured open, then clear and verify lock to lock at idle. Let the readiness monitors complete before an inspection.
Frequently asked questions
Can I drive with a P0553 code?
Yes. Power steering assist does not depend on this signal. Expect a stumble or stall when turning the wheel at idle, and the check engine light. Fix it to avoid stalling at low speed.
What is the difference between P0552 and P0553?
P0552 is the signal pinned low, usually a wire grounded or a switch stuck closed. P0553 is the signal pinned high, usually an open circuit: an unplugged connector, a broken wire, a lost ground or a device that never closes.
Why did P0553 appear after a belt, pump or alternator repair?
Because the PSP connector sits in that area and is easy to leave unplugged or half-seated, and a shredded belt cuts the harness beside it. Check the connector first.
How much does it cost to fix P0553?
Reseating a connector costs nothing. A wire repair is under an hour. A switch or sensor is an inexpensive part with a fluid top-up.
Related codes
- P0552: circuit low; see P0552. P0554: intermittent; see P0554.
- P0550 / P0551: circuit and range or performance; see P0550.
- P0505 to P0507: idle control codes, the symptom side; see P0507.
The code number itself tells you the family and the domain; how to read an OBD2 code number explains what each character means.