Worn or contaminated throttle position sensor internal tracks; Corroded, loose, or damaged TPS connector pins or wiring; Carbon buildup or mechanical binding in the throttle body preventing full sweep; Failed TPS reference voltage or ground circuit from the PCM; PCM software glitch or faulty PCM driver (rare); Aftermarket throttle body or TPS with incorrect resistance range

DTC codes / Mazda codes / P1124

P1124 · MazdaThrottle Position Sensor Signal Out Of Self Test Range

Q: What does code P1124 mean?

Throttle Position Sensor Signal Out Of Self Test Range. P1124 on Mazda vehicles means the powertrain control module (PCM) commanded the throttle position sensor (TPS) through its full sweep during a self-test and the returned signal fell outside the expected voltage range. The PCM detected that the TPS output did not rise and fall as predicted, indicating a faulty sensor, wiring problem, or mechanical binding in the throttle body.

P1124 on Mazda vehicles means the powertrain control module (PCM) commanded the throttle position sensor (TPS) through its full sweep during a self-test and the returned signal fell outside the expected voltage range. The PCM detected that the TPS output did not rise and fall as predicted, indicating a faulty sensor, wiring problem, or mechanical binding in the throttle body.

SystemPowertrain

Code typeMazda specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Check engine light illuminated, often with no other noticeable symptoms
Hesitation or stumble when accelerating from a stop
Erratic or surging idle quality
Reduced engine power or limp-home mode in some cases
Poor fuel economy or altered shift quality on automatic models

Common causes, most likely first

Worn or contaminated throttle position sensor internal tracks
Corroded, loose, or damaged TPS connector pins or wiring
Carbon buildup or mechanical binding in the throttle body preventing full sweep
Failed TPS reference voltage or ground circuit from the PCM
PCM software glitch or faulty PCM driver (rare)
Aftermarket throttle body or TPS with incorrect resistance range

How to diagnose and fix it

Connect a scan tool and read live TPS voltage while slowly opening the throttle by hand to confirm the signal is erratic or out of range
Inspect the TPS connector and wiring for corrosion, chafing, or loose pins, and repair as needed
Clean the throttle body and throttle plate with approved cleaner to remove carbon binding
Backprobe the TPS reference voltage (typically 5V) and ground circuits to verify they are stable
Replace the TPS with a quality OEM-equivalent part and perform a throttle position relearn or idle relearn procedure
If the signal remains out of range after replacement, check for a faulty PCM or wiring harness fault between the TPS and PCM

Why a clean throttle body often fixes P1124

Carbon buildup on the throttle plate can prevent the TPS from reaching its full self-test sweep, setting P1124 even when the sensor itself is healthy.
A TPS that tests fine with a multimeter can still fail the PCM self-test because the sweep is too fast for a meter to catch a dropout; use a scan tool with live graphing.
After replacing the TPS, many Mazda models require a throttle position relearn or idle relearn procedure, and skipping it can cause a repeat P1124 or poor idle.
Corroded pins at the TPS connector are a common missed cause, especially on older Mazdas exposed to road salt or humidity.
P1124 can be set by a binding throttle cable or pedal assembly that prevents the throttle plate from moving through its full range during the self-test.

Can I keep driving with P1124?

You can usually drive the vehicle to a repair shop, but avoid aggressive acceleration or heavy load because the PCM may limit power or shift quality. If the engine enters limp-home mode or stalls, stop driving and arrange a tow.

Tools that help

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Guidance is general and written for Mazda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.