Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

U1255 Class 2 Initialization Error - IPC

Wiring Diagram:






Circuit Description:
The IPC periodically requests information from other modules on the Class 2 serial data line.

DTC Will Set When:
The IPC requests information and the module which has that information is not "On-line."

Action Taken (By IPC):
The IPC will use default values for the information that it was requesting.

DTC Will Clear When:
The module with the information the IPC is requesting comes back "on-line."

Troubleshooting Hints:
1. If DTC U1255 is set, Clear DTCs and Cycle ignition. If DTC U1255 is still current, ensure that all the modules are functioning properly by establishing communications with each module on the Class 2 Data Bus.
2. Check CKT 1807 (PPL) for a intermittent open.
3. If OK, replace the IPC.