Rear Height Control System Troubleshooting

Toyota Prado 120 Series
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Introduction

This document provides troubleshooting steps for the Rear Height Control (RHC) system, also known as Toyota Enhanced Modulated Suspension (TEMS), found in some Toyota vehicles. The system is designed to automatically level the rear suspension and allow manual height adjustments.

Problem

The Rear Height Control system fails to auto-level. The height control switch does not function in either the “Hi” or “Lo” position, remaining at “N” (Normal). Compressor is not activating.

Possible Causes and Solutions

  1. Blown Fuses:

    • Check both the 10A and 50A fuses related to the RHC system.
      • SOLUTION: Replace any blown fuses with the correct amperage rating. Note: A blown 10A fuse may illuminate an “off” indicator near the height control display.

  2. Disconnected Height Control Switch Connector:

    • SOLUTION: Inspect the connector on the rear height control switch, located in the center console. Ensure the connector is properly seated and secure. A disconnected connector will prevent the system from functioning.

  3. System Deactivation:

    • Verify that the height adjustment system hasn’t been inadvertently turned off via a dedicated switch.

  4. Compressor Failure:

    • Check the compressor for functionality. You can bench test the compressor by removing it from the vehicle and applying power directly to it.
      • If the compressor runs when power is applied, the issue likely lies elsewhere.

  5. ECU Fault/Reset Required:

    • A diagnostic scan with a suitable scan tool (e.g., Toyota diagnostic tool) may be necessary to identify error codes or require a system reset.

Relevant Parts

  • 10A Fuse
  • 50A Fuse

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