Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC 91-1: SH-AWD Control Unit Programming Error
- Before you troubleshoot, review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
- DTC 91-1 is stored when the SH-AWD system update is not completed.
- Do not turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode while updating the SH-AWD system. If you do, the SH-AWD system can be damaged.
- Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
- Do the SH-AWD system update procedure (see SH-AWD® CONTROL UNIT UPDATE ).
- Check for DTCs with the HDS.
Is DTC 91-1 indicated?
YES - Substitute a known-good SH-AWD control unit (see SH-AWD® CONTROL UNIT REPLACEMENT ), and recheck. If the symptom/indication goes away with a known-good SH-AWD control unit, replace the original SH-AWD control unit (see SH-AWD® CONTROL UNIT REPLACEMENT ).
NO - Update is complete.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.