GM 23 Intake Air Temp Sensor Error Low Temp Indicated
How to read it
Code 23 reads as 2 flashes, pause, 3 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 23 mean?
Intake Air Temp Sensor Error Low Temp Indicated
Common causes of 23
- Open MAT or intake air temp sensor circuit
- Unplugged sensor connector
- Failed sensor reading far colder than actual air
- Corroded harness connector raising resistance
How to fix 23
- Compare scan tool air temp to actual ambient temperature
- Inspect the sensor connector and air cleaner duct wiring
- Measure sensor resistance against the factory temperature chart
- Repair the open circuit before replacing the sensor
- On carbureted models check the manifold air temp sensor in the intake
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 23. Include your vehicle, the issue and a source if you have one.