20 Fuel Pump Circuit Open
How to read it
Code 20 reads as 2 flashes, pause, 0 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 20 mean?
20. Fuel Pump Circuit Open. This code sets when your vehicle computer detects fuel pump circuit open.
Common causes of 20
- Failed in-tank fuel pump
- Open fuel pump power wire or a bad fuel pump relay
- Blown fuel pump fuse or fusible link
- Bad oil pressure switch on the pump prime circuit
How to fix 20
- Retrieve codes with a paperclip across ALDL pins A and B and count the Check Engine flashes
- Listen for the fuel pump prime at key on and check for pump power at the relay
- Check the fuel pump fuse or fusible link before replacing the pump
- Verify fuel pressure at the rail against spec
- Clear codes after the repair and recheck after a road test