AWD System Symptom Troubleshooting Index

Symptom	Diagnostic procedure	Also check for
Rear differential overheats	Fluid level too low Incorrect fluid type Incorrect tire diameter or wheel speed signal	Add recommended rear differential fluid . Drain and fill the differential with recommended rear differential fluid . Check tire diameter - Refer to: Design Specifications (2019 - 2023) or Design Specifications (2022 - 2023) . Check for VSA system DTC .
Rear differential leaks fluid	Fluid level too high Clogged breather hose Worn or damaged oil seal Damaged sealing washer Loose mounting bolts Deterioration of liquid gasket	Lower rear differential fluid to proper level . Clean or replace the breather hose . Replace faulty oil seal . Replace faulty sealing washer. Recheck torque of mounting bolts. Apply liquid gasket evenly to sealing surface.
HDS does not communicate with vehicle	DLC circuit error	Troubleshoot the DLC circuit - Refer to: DLC Circuit Troubleshooting (2019 - 2023) or DLC Circuit Troubleshooting (2022 - 2023) .
HDS does not communicate with SH-AWD® control unit	SH-AWD® system circuit error	Do the symptom troubleshooting for HDS does not communicate - Refer to: AWD System Symptom Troubleshooting - HDS does not communicate .
AWD indicator does not go off, and no DTCs are stored	AWD indicator circuit error	Do the symptom troubleshooting for AWD indicator does not go off, and no DTCs are stored - Refer to: AWD System Symptom Troubleshooting - AWD indicator does not go off, and no DTCs are stored
Will not go into AWD mode, Poor traction, Poor acceleration (at start), Poor climbing ability, SH-AWD® system is stuck in AWD mode	SH-AWD® system defective Rear differential assembly defective	Do the symptom troubleshooting for will not go into AWD mode, poor traction, poor acceleration (at start), poor climbing ability, SH-AWD® system is stuck in AWD mode - Refer to: AWD System Symptom Troubleshooting - Will not go into AWD mode, Poor traction, Poor acceleration (at start), Poor climbing ability, SH-AWD® system is stuck in AWD mode .
Abnormal noise	Interference with items such as wire harness Fluid level too low Incorrect fluid type Damaged rear differential assembly Rear differential pump motor defective Incorrect installation Internal failure Rear differential assembly defective Fluid leaks Internal failure	NOTE: Compare the noise with a known-good vehicle of the same type. Make sure that noises you hear are not coming from other systems. Repair or remove interference item. Add recommended rear differential fluid . Drain and fill the differential with recommended rear differential fluid . Repair rear differential assembly . Replace rear differential pump motor . Replace faulty rear differential internal part .