What causes GM code 52?

Missing or loose CALPAK chip in the ECM Incorrect CALPAK for the vehicle Corroded chip contacts Failing ECM socket on high mileage units

How do I fix GM code 52?

Turn the key off and verify the CALPAK is present and fully seated Inspect chip contacts for corrosion and clean gently Verify the CALPAK part number matches the vehicle Clear codes and confirm the code does not return Replace the chip or ECM only after seating and part number check good

52 Fuel Calpak Incorrect Or Missing

Q: What does GM code 52 mean?

GM code 52 — Fuel Calpak Incorrect Or Missing. Applies to 1982-1995 GM cars and C/K trucks with CALPAK equipped ECMs.

Make: GM (1982-1995)
Category: Powertrain - Computer and Auxiliary Controls
Severity: Check Engine Light
Applies to: 1982-1995 GM cars and C/K trucks with CALPAK equipped ECMs

How to read it

Code 52 reads as 5 flashes, pause, 2 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 52 mean?

52 — Fuel Calpak Incorrect Or Missing. This code sets when your vehicle computer detects fuel calpak incorrect or missing.

Common causes of 52

Missing or loose CALPAK chip in the ECM
Incorrect CALPAK for the vehicle
Corroded chip contacts
Failing ECM socket on high mileage units

How to fix 52

Turn the key off and verify the CALPAK is present and fully seated
Inspect chip contacts for corrosion and clean gently
Verify the CALPAK part number matches the vehicle
Clear codes and confirm the code does not return
Replace the chip or ECM only after seating and part number check good