What causes GM code 33?

MAP sensor vacuum hose cracked or disconnected Failed MAP sensor reading high voltage Open sensor ground circuit Intake vacuum leak lowering manifold vacuum

How do I fix GM code 33?

Inspect the MAP vacuum hose for cracks and secure connections Read MAP voltage through the ALDL port at idle and with the engine off Test sensor voltage against known vacuum readings Repair vacuum leaks before replacing the sensor Replace the sensor only if voltage stays high with good vacuum applied

33 MAP Sensor Circuit Error Signal High

Q: What does GM code 33 mean?

GM code 33 — MAP Sensor Circuit Error Signal High. Applies to 1982-1995 GM cars and C/K trucks, Camaro, Corvette.

Make: GM (1982-1995)
Category: Powertrain - Fuel/Air Metering
Severity: Check Engine Light
Applies to: 1982-1995 GM cars and C/K trucks, Camaro, Corvette

How to read it

Code 33 reads as 3 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.

What does GM code 33 mean?

33 — MAP Sensor Circuit Error Signal High. This code sets when your vehicle computer detects map sensor circuit error signal high.

Common causes of 33

MAP sensor vacuum hose cracked or disconnected
Failed MAP sensor reading high voltage
Open sensor ground circuit
Intake vacuum leak lowering manifold vacuum

How to fix 33

Inspect the MAP vacuum hose for cracks and secure connections
Read MAP voltage through the ALDL port at idle and with the engine off
Test sensor voltage against known vacuum readings
Repair vacuum leaks before replacing the sensor
Replace the sensor only if voltage stays high with good vacuum applied