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Error code reference
Denso Air Conditioner Error Code E11
STI module communication error: communication failure between STI module and microcomputer on relay board detected for at least 40 seconds.
SourceDENSO CM 25 Air Conditioner - Full Service Manualp. 45, 53
Diagnostic procedure
The full E11 procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Check all wire connections on the relay board, then RESET the controller. If error persists, replace the relay board.
SourceDENSO CM 25 Air Conditioner - Full Service Manualp. 45, 53
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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Where this code is documented
1 manual in the MyPros+ library documents this code for Denso air conditioner.
Models covered by the manuals that document this code
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