Front airbags over inflate...

Some info from my 94 service manual:

"A magnet mounted in the lower slide portion of the air suspension height sensor moves relative to the air suspension height sensor housing, generating a signal that is sent to the control module".

"The control module supplies the air suspension sensor with 5 volts for power through circuit 431 (PK/W). Ground to the air suspension height sensor is supplied through circuit 432 (PK/BK)".
 
Since there is a magnet in the sensor and the sensor sends a signal to the module even when the magnet is not moving, I would guess the sensor itself is a "Hall Effect" device.
 
If you already swapped out the height sensors and the air ride module, I would check the wiring and connectors going to and from the air ride module.

I would start with the height sensor power supply, ground, and signal wires. Also I'd take a good look at the connectors at the air ride module and height sensors.
 
driller said:
The voltages appear to reflect exactly what you describe... the front is high.

Assuming the voltages from the sensors are alright, let's back up and diagnose the general system according to the manual(without using the Super Star II Tester).

OA1:"QUICK" WIRING AND CIRCUIT CHECKS

Setup:

  • Air suspension switch ON.
  • Control module GRAY connector disconnected.
  • Control module BLACK connector disconnected.

Pinpoint tests:

  • Module ground - pin 32(-) to battery negative terminal - resistance must be less than 1 ohm.
  • Module power - pin 1(+) to pin 32(-) AND pin 21(+) to pin 32(-) - battery voltage.
  • Ignition signal - pin 4(+) to pin 32(-) - ignition off = zero / ignition on = battery voltage.
  • Door switch signal - pin 5(+) to pin 32(-) - both doors closed = zero / either door open = battery voltage.
  • Star Tester Input (STI) line - pin 6(+) to pin 32(-) - voltage = zero / resistance = greater than 1000 ohms.
  • Air Suspension Switch - pin 11(+) to pin 32(-) - switch OFF = battery voltage / switch ON = zero.
  • Star Tester Output (STO) Line - pin 12(+) to pin 32(-) - ignition OFF = zero voltage / ignition ON = 6.0 volts.
  • Spring Solenoids - pins 14/32(Left Front) / pins 15/32(Right Front) / pins 16/32(Left Rear) / pins 17/32(Right Rear) - resistance 14-18 ohms(nominal 16 ohms).
  • Compressor Relay Control Line - pin 18(+) to pin 32(-) - battery voltage.
  • Vent Solenoid - pin 30 to pin 32 - resistance 19-24 ohms(nominal 21 ohms).

If all the pinpoint tests pass, we can force outputs.

OA2: FORCING OUTPUTS

If the measurements of voltages and resistance have fallen within the given limits, the system output may now be tested. If the voltages and resistance are not within limits, service the faults before continuing.

The following tests are done with the control module black and gray connectors disconnected.

Use a jumper with an in-line fuse rated at not more than 5 amps.

Connect the jumper between the battery supply pin, pin 1 and the individual solenoid pins.

  • Left Front - pin 14
  • Right Front - pin 15
  • Left Rear - pin 16
  • Right Rear - pin 17
  • Vent solenoid - pin 30

Each solenoid should click as power is applied and should click each time power is removed. A second person listening at the solenoid locations may be necessary.

Connect the jumper between the ground pin, pin 32, and the compressor relay control line at pin 18.

The air suspension system compressor should begin running when ground is applied to pin 18 and it should stop running when the ground is removed.

Patience and persistance will finally prevail. :rolleyes:
Click to expand...

Ok......I checked all of the connections everywhere and all of it looks good.
I did all the test's and what I came up with is that all was good except the Star Tester Input (STI) line - pin 6(+) to pin 32(-) - voltage = zero / resistance = greater than 1000 ohms....I could not get anything at all to show..all the other ohm test came out fine but no matter what I did there was nothing at all on that one...:confused: Secondly the Right Rear on the spring solenoids was at 23 ohms when the other three were at 17. And lastly when I did the force outputs the Left Rear-pin 16 clicked but also the interior lights went out and the message center said to Check Traction Control :eek:
After all that work now the pump refuses to come on and immediately upon turning the key it says Check Air Suspension. I did that check by grounding the wire under the hood for the little auto check it does and just as before it clicked each valve and the pump vent then kicked on the pump and that was it.....I am so frustrated now!
 
What kind of meter are you using? What range do you use for the resistance test? The STI pin 6 should show 0 volts and that's what you're getting?

That circuit is the same wire that you are grounding under the hood to run the self test. It sounds to me that that circuit is OK. If there was a problem with that, the self test wouldn't run at all.

Is your battery fully charged? Have you been driving the car?
 
I am using an automotive digital volt and ohm analyzer. The STI line/pin 6 was supposed to have greater than 1000 ohm's when it read nothing on all settings. I was not looking for volts on that pin. Yes the car is charged and was actually running except when the test called for the ignition to be off. Before when it would air up I would cut the switch in the trunk to keep it from over inflating the front and yes I would drive it up and down the road. I actually put the new airbags and valves on while I was on vacation at myrtle beach after getting the car in Florida, and I drove this car all the way back to Texas. What I really don't understand is why the forced valve opening on pin 16/left rear would click but at the same time turn off the interior lights and give me a check traction control warning. I did this several times with the same result. Also the resistance on the
valves was all at 17 ohms except the right/rear that was at 23.
 
Since the car will no longer air up does anyone know how I can manually make it go up so that I can get it out of the way? Right now it is sitting on the ground and the ground is not level enough to move it :( It has no more air because I let it out to see if it would stop at the right point but now it does nothing so Its stuck.
 
The reason I asked about the battery was because when the interior lights went out and the traction control light came on that sounds like battery problems. These vehicles do some strange things when there is a battery or battery connection problem. If the battery is charged, it might be just bad battery connections adding to your troubles now.

If your meter is showing infinity ohms on all settings, when you measure the STI circuit, that is greater than 1000 ohms, so I'd say that that's OK.

The resistance on your right rear solenoid sounds a little high, but I don't think that that's your problem because you're still having troubles with the front of the system (pump not stopping when the front is at the proper height) and the system adjusts the front first before the rear.

The next thing I would do is plug the system back together and check to make sure that you have good power (5 volts) and ground going to the height sensors.

One of the error codes that can be generated by the air ride system is a code for bad ride height sensor power supply.
 
billcu said:
The reason I asked about the battery was because when the interior lights went out and the traction control light came on that sounds like battery problems. These vehicles do some strange things when there is a battery or battery connection problem. If the battery is charged, it might be just bad battery connections adding to your troubles now.

If your meter is showing infinity ohms on all settings, when you measure the STI circuit, that is greater than 1000 ohms, so I'd say that that's OK.

The resistance on your right rear solenoid sounds a little high, but I don't think that that's your problem because you're still having troubles with the front of the system (pump not stopping when the front is at the proper height) and the system adjusts the front first before the rear.

The next thing I would do is plug the system back together and check to make sure that you have good power (5 volts) and ground going to the height sensors.

One of the error codes that can be generated by the air ride system is a code for bad ride height sensor power supply.
Click to expand...

Yup.....Perfect 5.00 volts to the sensors.
 
mk8fanatic said:
Ok......I checked all of the connections everywhere and all of it looks good.
I did all the test's and what I came up with is that all was good except the Star Tester Input (STI) line - pin 6(+) to pin 32(-) - voltage = zero / resistance = greater than 1000 ohms....I could not get anything at all to show..all the other ohm test came out fine but no matter what I did there was nothing at all on that one...:confused: Secondly the Right Rear on the spring solenoids was at 23 ohms when the other three were at 17. And lastly when I did the force outputs the Left Rear-pin 16 clicked but also the interior lights went out and the message center said to Check Traction Control :eek:
After all that work now the pump refuses to come on and immediately upon turning the key it says Check Air Suspension. I did that check by grounding the wire under the hood for the little auto check it does and just as before it clicked each valve and the pump vent then kicked on the pump and that was it.....I am so frustrated now!
Click to expand...

First, the resistance reading on pin 6 to pin 32... when you say NOTHING - does that mean the resistance was ZERO or INFINITY?

Second, the resistance reading of 23 ohms on the right rear solenoid is out of spec. It could perhaps be a problem with the harness connector to the solenoid.

Third, did grounding the compressor relay control line at pin 18 make the compressor run?

mk8fanatic said:
What I really don't understand is why the forced valve opening on pin 16/left rear would click but at the same time turn off the interior lights and give me a check traction control warning. I did this several times with the same result. Also the resistance on the
valves was all at 17 ohms except the right/rear that was at 23.
Click to expand...

Sounds like a short of somekind. Time to break out the EVTM OR have the Star Tester diagnose the system. Especially if you get a 'check air ride' warning immediately upon turning on the key - that signifys what is known as a 'hard fault'.

mk8fanatic said:
Since the car will no longer air up does anyone know how I can manually make it go up so that I can get it out of the way? Right now it is sitting on the ground and the ground is not level enough to move it :( It has no more air because I let it out to see if it would stop at the right point but now it does nothing so Its stuck.
Click to expand...

IF grounding the compressor relay control line at pin 18 causes the compressor to run, perhaps you can force the compressor to run AND force the solenoids open?
 
Victory At Last!!!

Victory At Last!!!

I went to the front left wheel and jacked it up and just to see what the car would do I depressed the sensor and low and behold it aired up. So obviously the I tried one of the other sensors that I took off initially and one of them worked! I ran the self test and for the first time it went through the whole proses with out fault. Finally I was able to lower the front via sensor bracket repositioning mod. For all of you with your helpful expertise I would like to thank you very much....I am just glad that LOD exists to ensure all mark viii owners have a place to mingle and share their knowledge about a car that we all love.

So without further a due I would like to present the second generation two mark viii in my collection that I bought for 1,500 with 131,000 miles and just added a column, front air struts,used sensors, and air pump. Oh... and a little blood sweet and tears!

000_2212.jpg

000_2221.jpg

000_2206.jpg
 
Last edited:
Glad to hear this!

It turned out to be a bad height sensor after all.:)

Like JP said:

"Patience and persistance will finally prevail".

The Mark looks great!
 
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