Carbon buildup or wear inside the electronic throttle body causing the throttle plate to stick; Faulty throttle position sensor or integrated throttle body assembly; Damaged, corroded, or loose wiring in the TP controlled circuit; Poor electrical connection at the throttle body or PCM connectors; PCM software issue or internal fault (less common); Aftermarket or improperly installed throttle body; Intake air leaks or vacuum leaks affecting throttle control

DTC codes / Mazda codes / P1191

P1191 · MazdaTP Controlled Circuit

Q: What does code P1191 mean?

TP Controlled Circuit. P1191 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an out-of-range condition in the throttle position (TP) controlled circuit, which typically involves the TP sensor signal or the motor control circuit inside the electronic throttle body. The PCM monitors the expected voltage or current on this circuit and sets the code when the actual value deviates from the commanded value for a calibrated time, often due to a faulty throttle body, wiring issue, or poor connection.

P1191 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an out-of-range condition in the throttle position (TP) controlled circuit, which typically involves the TP sensor signal or the motor control circuit inside the electronic throttle body. The PCM monitors the expected voltage or current on this circuit and sets the code when the actual value deviates from the commanded value for a calibrated time, often due to a faulty throttle body, wiring issue, or poor connection.

SystemPowertrain

Code typeMazda specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine power or limp mode, limiting vehicle speed
Hesitation or stumble during acceleration
Unstable or fluctuating idle speed
Poor throttle response or delayed acceleration
In rare cases, the engine may stall or refuse to start

Common causes, most likely first

Carbon buildup or wear inside the electronic throttle body causing the throttle plate to stick
Faulty throttle position sensor or integrated throttle body assembly
Damaged, corroded, or loose wiring in the TP controlled circuit
Poor electrical connection at the throttle body or PCM connectors
PCM software issue or internal fault (less common)
Aftermarket or improperly installed throttle body
Intake air leaks or vacuum leaks affecting throttle control

How to diagnose and fix it

Inspect the throttle body and intake tract for carbon buildup or obstructions; clean the throttle bore and plate with approved cleaner
Check all wiring and connectors between the throttle body and PCM for damage, corrosion, or looseness; repair as needed
Perform a throttle body calibration or relearn procedure using a scan tool after cleaning or replacement
Test the throttle position sensor and throttle motor circuits with a multimeter for opens, shorts, or excessive resistance
If the throttle body is faulty, replace it with a quality OEM or equivalent unit and perform the calibration
Verify the repair by clearing the code and test-driving the vehicle under various conditions to ensure the code does not return
If the code persists, check for PCM software updates or consult a Mazda specialist for further diagnosis

Common Misdiagnosis Traps for P1191

Many technicians replace the throttle body immediately, but a dirty throttle body often causes this code and can be fixed with a thorough cleaning and calibration.
A weak battery or poor ground connection can cause voltage drops that mimic a faulty throttle body, so always check battery health and grounds first.
The TP controlled circuit may include the accelerator pedal position sensor on some Mazda models, so inspect that circuit as well before condemning the throttle body.
After replacing the throttle body, a relearn procedure is mandatory; skipping it will cause the code to return even with a new part.
Intermittent wiring faults can be temperature or vibration sensitive, so wiggle-test the harness while monitoring live data to catch them.

Can I keep driving with P1191?

You can usually drive the vehicle to a repair shop, but avoid aggressive acceleration or heavy loads because the engine may enter limp mode without warning. If the engine stalls or loses power suddenly, pull over safely and seek immediate assistance.

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.