Faulty power steering pressure switch (stuck open, stuck closed or internal failure); Damaged, corroded or loose connector at the pressure switch; Open circuit, short to earth or short to voltage in the switch wiring; Low power steering fluid level or air in the system giving abnormal pressure readings; Power steering pump or pressure fault causing pressure outside the expected range; Fault inside the engine control unit.

P1650

Power Steering Pressure Switch Out Of Range Fault.

Mazda
Powertrain
Manufacturer code
Low severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
6: AreaComputer and output circuits
50: FaultThe specific fault in that area

What it means

On Mazda, P1650 means the engine control unit has found a fault in the power steering pressure (PSP) switch circuit or signal. The switch tells the ECU when the steering is under heavy load, such as at full lock or parking speeds, so it can raise idle speed. The code sets when the switch signal is out of its expected range or does not change state as expected, for example stuck on, stuck off or a wiring fault.

Symptoms

Engine idle dips or stalls when turning the steering to full lock
Idle speed unstable or too low when parking
Engine management warning light on
Heavy or inconsistent steering feel at low speed
Idle speed does not rise when the steering is turned

Possible causes

Faulty power steering pressure switch (stuck open, stuck closed or internal failure)likely
Damaged, corroded or loose connector at the pressure switchlikely
Open circuit, short to earth or short to voltage in the switch wiringpossible
Low power steering fluid level or air in the system giving abnormal pressure readingspossible
Power steering pump or pressure fault causing pressure outside the expected rangepossible
Fault inside the engine control unitrare

How to diagnose

Read the stored codes and freeze frame data, noting engine speed, load and whether the steering was being turned when the code set
Check the power steering fluid level and condition, and look for leaks around the pump, hoses and rack
Inspect the pressure switch connector and wiring for damage, corrosion, chafing or fluid contamination
Using live data, watch the PSP switch state at idle and while turning the steering to full lock; it should change state under load
Check the switch circuit for supply, signal and earth against the model's wiring diagram, and test for continuity and shorts
Test the switch itself against the manufacturer's specification for the model and engine
Check power steering pump operation and system pressure if the switch tests good but the signal does not change
Clear the code and road test to confirm the fault does not return

How to fix

Replace the power steering pressure switch if it fails testing
Repair or replace damaged wiring or clean and secure the connector
Top up or renew power steering fluid and bleed air from the system as per the manufacturer's procedure
Repair or replace the power steering pump or faulty pressure components if pressure is abnormal
Diagnose and, only if proven faulty, replace the engine control unit

Can I keep driving?

Low severity

The car can normally be driven, but idle may dip or stall when parking or turning at low speed. Get it checked soon, especially if the steering feels heavy or the engine stalls.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.