B1550-H

DTC B1550-H / B1550-L

DTC Detecting Condition and Trouble Area






Circuit Diagram










DTC Confirmation Procedure

1) Start engine and operate A/C system.

DTC Troubleshooting

1. DTC check

Push engine switch to change ignition mode to "ON".
Push engine switch to change ignition mode to "OFF".
Push engine switch to change ignition mode to "ON" and check DTC.

Is DTC B1550-H or B1550-L still detected?
YES -
Go to Step 2.
NO -
Intermittent trouble.

2. Communication circuit check

Disconnect "G20" and auto A/C panel connectors.
Check the following points.
- Resistance of "RED/GRN" wire circuit: less than 1 ohms
- Resistance of "RED/GRN" wire circuit between auto A/C panel and ground: infinity

Are they in good condition?
YES -
Replace HVAC control module and recheck DTC. HVAC Control Module Removal and Installation
NO -
Repair or replace defective wire harness.