P0688 - Jeep stalled and won't start again - ASD error

[anarky321]

i need a little help on how to proceed through the diagnostic steps here

i tried jumping the ASD relay with a bridge, and it still wont start

the only code is 0688

 

[JeepJeezy]

Did you try swapping relays? Also what year are we working with?

 

[Chris]

i need a little help on how to proceed through the diagnostic steps here

i tried jumping the ASD relay with a bridge, and it still wont start

the only code is 0688

Since jumping the ASD relay didn’t help, here’s a step-by-step approach to narrow it down:

• First, confirm that you have power to the ASD relay. You can use a multimeter or test light to check both the coil and the terminals.
• Make sure there are no blown fuses related to the ASD or fuel pump circuits. Sometimes a blown fuse can cause multiple issues.
• It’s possible the relay itself could be faulty. If you have access to another relay of the same type, try swapping it out to see if that resolves the issue.
• Check the wiring and connectors for any signs of damage, corrosion, or loose connections. Pay special attention to the connector for the PCM (Powertrain Control Module) as issues here can often lead to ASD errors.
• Ensure that all ground connections are secure and free from corrosion. A bad ground can lead to erratic behavior in the electrical system.
• Since the P0688 code indicates a problem with the ASD relay control circuit, it’s worth considering whether there’s an issue with the PCM itself. If everything else checks out, you might want to look into getting the PCM tested or replaced.

Good luck, and let us know how it goes!