GM 25 Intake Air Temp Sensor Error High Temp Indicated
How to read it
Code 25 reads as 2 flashes, pause, 5 flashes on the check-engine light. Jump terminals A and B on the ALDL connector with the key off, then turn the key on with the engine off and count the check-engine flashes.
New to flash codes? The How to Read GM OBD-I Codes with a Paperclip walks through the test and what the numbers mean. The general OBD-I guide covers the rest.
What does GM code 25 mean?
Intake Air Temp Sensor Error High Temp Indicated
Common causes of 25
- Shorted MAT or intake air temp sensor
- Signal wire shorted to ground
- Failed sensor reading far hotter than actual air
- Heat soaked wiring melted against exhaust parts
How to fix 25
- Compare scan tool air temp to actual ambient temperature
- Unplug the sensor and check whether the reading swings cold
- Inspect wiring for melted insulation near hot parts
- Measure sensor resistance against the factory temperature chart
- Replace the sensor only after a wiring short is ruled out
Source
Qualified source review
Sources and review
Review: qualified. Read the source limits below.
- GM and Chevrolet OBD1 Trouble Codes (ALDL Fault Code List)
live reference page (troublecodes.net)
Supports: code identity and GM meaning
Fetched directly. Single publisher, so the record is qualified, not verified. Causes and check order are curator-written from the circuit the code names.
https://www.troublecodes.net/gm/
Last updated 2026-09-19.
Report a correction for 25. Include your vehicle, the issue and a source if you have one.