Land Rover Discovery 4 Suspension Fault

I own a Land Rover Discovery 4, which I took to a local dealership for wheel alignment before a countryside trip. The technician noticed it was leaning more to the left, and I suspected the air suspension might be deflated. After inflating the air strut, an error message appeared on the dash stating "Suspension inflating slowly." Deciding to take a different vehicle, I began driving the Discovery home, but the suspension fully deflated during the trip, leaving the car flat on the road. I managed to raise it to off-road mode and left it in that setting for three days.

Upon returning, I scanned for error codes and found:

- **C1A04-78**: Front right height sensor (Intermittent)
- **C1A07-62**: Cross articulation (Intermittent)
- **C112F-72**: Air spring valve (Intermittent)

I inspected the front left air strut for leaks using soapy water but found none, and the hose and valve connections appeared fine. After deflating the air strut to see if it would reinflate, the suspension failed to restore normal height, even in off-road mode. Further diagnostics revealed the following permanent error codes, and the system continues to display a "Suspension Fault":

- **C1A04-78**: Front right height sensor (Permanent)
- **U3000-53**: Control module (Permanent)
- **U3000-55**: Control module (Permanent)

Any insights on how to resolve this suspension issue?

First thing todo is to test your front right height sensor, sounds like it could do with a calibration if it's leaning as well. Leaks etc unless they are catastrophic (I.e you can hear hissing all the time) will not cause leaning, it will be down to faulty height sensor or duff calibration.

Tech might have knocked the wires to the height sensors, one on each corner, the sensor plugs and the wires are known weak points.

TheMunster said:

First thing todo is to test your front right height sensor, sounds like it could do with a calibration if it's leaning as well. Leaks etc unless they are catastrophic (I.e you can hear hissing all the time) will not cause leaning, it will be down to faulty height sensor or duff calibration.

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How can I get the car to inflate? It is currently on the ground and won't inflate due to a suspension issue.

Which scan tool do you have?

If it won't raise and the only code you have is the above code for front right sensor then I would pursue testing that sensor. If you can view live data then pop off the end of the arm that connects to the car and move the arm around and see if the live data shows full range of movement. If you can't view livedata you can use a scope to show the signal while you move the sensor arm. If you don't understand what I mean then it's best to lube up and take it to a local indy.

Obvious warning about working on a live and faulty air suspension set up - car could raise or drop without warning etc

TheMunster said:

Which scan tool do you have?

If it won't raise and the only code you have is the above code for front right sensor then I would pursue testing that sensor. If you can view live data then pop off the end of the arm that connects to the car and move the arm around and see if the live data shows full range of movement. If you can't view livedata you can use a scope to show the signal while you move the sensor arm. If you don't understand what I mean then it's best to lube up and take it to a local indy.

Obvious warning about working on a live and faulty air suspension set up - car could raise or drop without warning etc

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I have SDD installed on my laptop and connect to the vehicle using a Mongoose VCI.

This is the pending DTC for the Discovery 4. Please guide me on how to perform calibration.

Kayvoh87 said:

I inspected the front left air strut for leaks using soapy water but found none,

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Thought it was the front right that gave the issue?

Does the compressor run?
Inflating slowly is a sign of a weak compressor or a leak.

But also check the connector for that corner being clean and tight.

J

marjon said:

Thought it was the front right that gave the issue?

Does the compressor run?
Inflating slowly is a sign of a weak compressor or a leak.

But also check the connector for that corner being clean and tight.

J

Click to expand...

Yes the compressor is running