What causes P1121 on a Ford?

Dirty MAF sensor under-reporting airflow for the throttle angle Vacuum leak adding air the MAF never measured Failing TPS reporting the wrong angle Restricted air intake between the filter and throttle PCM software needing an update

How do I fix P1121 on a Ford?

Clean the MAF sensor first — it is the usual cause of the mismatch Smoke test the intake for unmetered air Graph TPS against MAF and look for the point of disagreement Check the air filter and duct for restriction Test the TPS sweep before condemning either sensor

P1121 Throttle Position Sensor Inconsistent with Mass Air Flow Sensor

Q: What does P1121 mean on a Ford?

P1121 — Throttle Position Sensor Inconsistent with Mass Air Flow Sensor. Applies to F-150, Mustang, Explorer, Ranger.

Category: Powertrain - Fuel/Air Metering
Severity: Check Engine Light
Applies to: F-150, Mustang, Explorer, Ranger

What does P1121 mean on a Ford?

P1121 — Throttle Position Sensor Inconsistent with Mass Air Flow Sensor. This Ford-enhanced code applies to F-150, Mustang, Explorer, Ranger.

Common causes of P1121

Dirty MAF sensor under-reporting airflow for the throttle angle
Vacuum leak adding air the MAF never measured
Failing TPS reporting the wrong angle
Restricted air intake between the filter and throttle
PCM software needing an update

How to fix P1121

Clean the MAF sensor first — it is the usual cause of the mismatch
Smoke test the intake for unmetered air
Graph TPS against MAF and look for the point of disagreement
Check the air filter and duct for restriction
Test the TPS sweep before condemning either sensor