Rear Air Suspension Troubleshooting and Repair (Toyota Prado 120)

Toyota Prado 120 Series
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Introduction

This guide provides information on troubleshooting and repairing the rear air suspension system on a Toyota Prado 120, specifically addressing issues related to the air compressor and system faults.

Problem

The vehicle’s rear air suspension is not inflating, causing it to sit on the bump stops. The air compressor may be non-functional, and the airbags may show signs of wear and cracking. The vehicle may exhibit issues shifting out of neutral.

Diagnosis

  1. Airbag Inspection: Visually inspect the airbags for cracks, tears, and general deterioration. Leaks are a common cause of compressor issues.
  2. Compressor Operation: Determine if the compressor is receiving power. If power is present, confirm the compressor is actually running, but be aware it may shut down after a short time with a fault.
  3. Fault Code Reading: Use a compatible code reader to check for suspension-specific fault codes. Standard code readers may not access these codes. There are approximately eight different fault codes specific to the compressor system.
  4. Manual Inflation Test: Remove the airbags and lightly inflate them with an external compressor to check for leaks. This can also be done while the bags are still installed on the vehicle.

Solution

The most common cause of this issue is a leak in the airbags. Replacing the airbags is often the first step in resolving the problem.

Compressor Reset Information

The air suspension system is designed to protect itself. The compressor will shut down and enter a fault state under specific circumstances:

  • If the compressor runs for longer than 2 minutes it can go into a fault if a leak is detected.

  • First fault: Resets after 10 minutes.

  • Repeated fault: Shuts down for 70 minutes.

  • Potential Reset Procedure: Clear any logged fault codes using a compatible scan tool.

Relevant Parts

  • Replacement Airbags: Firestone airbags (available through Airbag Man) are a potential replacement option.
  • Alternative Airbags: Consider purchasing new airbags from partsouq or amayama.

Additional Notes

  • If the H-N-L (High-Neutral-Low) selector is not functioning, it can impact the operation of other systems.

This technical summary was auto-generated based on recovered archives. Do not rely on its factual accuracy. Refer to the original thread. Source: View Original Conversation

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