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89 GL replacement EGR Vacuum solenoid and Air charge temp sensor


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Both codes 34 and 35 are flashing on the LED Under the steering column. Most of what I find online supports the same information that it is the two components or systems I have listed in the title.

 

I am capable of changing things on vehicles, and usually there is a wealth of information, but for some reason not mine.

 

Is there a clear demonstration video or a list of how to diagnose why there may be a malfunction in the solenoid/ system? I would hope  I can change the part myself, provided access is not too complicated. Also How can I tell if the air charge sensor is malfunctioning versus the rest of the circuit? I am having a difficult time clearly identifying these components under the hood. the more detail the better. 

I am hoping to find a manual specific to this vehicle without the ambiguities that a manual covering different models might have.

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89s don`t have seperate air charge temp/ sensors.

You are looking at the wrong chart.

 

Code 35 is for the purge solenoid.

There is a picture here http://www.ultimatesubaru.org/forum/topic/157839-loyal-wont-start-need-help-plea/

It is located on the RH side of the engine.

Test it by unplugging and putting an ohmmeter or 12 volts across it.It should click w/12 volts or read about 36 ohms.

Pretty common for the coil to be open.

 

Code 34 is for the EGR.

Normally this indicates an open EGR solenoid coil.

The EGR solenoid looks just like the purge solenoid evcept it has a white plug.

It is located just slightly towards the centre of the car from the purge solenoid.

Test it the same way as the purge solenoid.

 

Since you presumably have a california spec car there is another possibility for code 34.

They have an egr temp.sensor that detects whether there is actually any EGR flow.

The code will set on california cars if the tubes are plugged or the sensor is wonky.(or the solenoid is bad)

Check the solenoid first.

I have an EGR solenoid if you need one.

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89s don`t have seperate air charge temp/ sensors.

You are looking at the wrong chart.

 

Code 35 is for the purge solenoid.

There is a picture here http://www.ultimatesubaru.org/forum/topic/157839-loyal-wont-start-need-help-plea/

It is located on the RH side of the engine.

Test it by unplugging and putting an ohmmeter or 12 volts across it.It should click w/12 volts or read about 36 ohms.

Pretty common for the coil to be open.

 

Code 34 is for the EGR.

Normally this indicates an open EGR solenoid coil.

The EGR solenoid looks just like the purge solenoid evcept it has a white plug.

It is located just slightly towards the centre of the car from the purge solenoid.

Test it the same way as the purge solenoid.

 

Since you presumably have a california spec car there is another possibility for code 34.

They have an egr temp.sensor that detects whether there is actually any EGR flow.

The code will set on california cars if the tubes are plugged or the sensor is wonky.(or the solenoid is bad)

Check the solenoid first.

I have an EGR solenoid if you need one.

Thank you, I will reply about the solenoid as soon as I get it tested. You've given me more information here than 2 whole days  of searching.

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89s don`t have seperate air charge temp/ sensors.

You are looking at the wrong chart.

 

Code 35 is for the purge solenoid.

There is a picture here http://www.ultimatesubaru.org/forum/topic/157839-loyal-wont-start-need-help-plea/

It is located on the RH side of the engine.

Test it by unplugging and putting an ohmmeter or 12 volts across it.It should click w/12 volts or read about 36 ohms.

Pretty common for the coil to be open.

I tested the purge solenoid and it showed 36 ohms unplugged. I plugged it back and tested from the back of the plug harness with one lead  and the other lead to positive terminal of the battery with a 12.76 volt reading. My question is does this information confirm: 

A. a functioning solenoid

B. the circuit is intact

C. this error code is being caused by a malfunction of a system prior to this solenoid in the ergr?

 

I pulled out the EGR flow sensor and it was coated with carbon, I cleaned it and reinstalled it. Can I test it the same way as with the solenoid to see if it is functioning?

 

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A. No,it only confirms that is functional electricly,but this is all that matters as far as the code is concerned.

 For a full functionality test you would need to power it up and confirm the valve opens and closes.

 

B. No.It only confirms the power supply(even that not really)

    ECU operates the solenoid by connecting ground to the always powered solenoid.

    This does not check the ground side of the circuit.

    A high resistance connection on the power side could give full voltage to an ungrounded solenoid but have low voltage

w/the ground connected and current flowing.

 

C. I think so.Probably a bad harness connector especially since the EGR sets a code too.

 

The EGR temp sensor should be over 250 ohms unplugged.

This one will set code 55 not 34.

See page 71 section 2-7 of the ea82 manual mentioned above.

Edited by naru
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I would check for near zero ohms from the other wire to the appropriate wire on your ECU with it disconnected from the ECU.

 

That's all there is to it.

 

A constant 12v+ on one wire and a switched 12v- to the other wire from the ECU.

Do you mean I should disconnect the solenoid and test the harness leads that plug into the solenoid? Is there a bit more detailed information for how to test for positive/negative voltage?

Is there a secondary connection to the ecu under the steering column that could be checked?

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Do you mean I should disconnect the solenoid and test the harness leads that plug into the solenoid? Is there a bit more detailed information for how to test for positive/negative voltage?

Is there a secondary connection to the ecu under the steering column that could be checked?

 

See page 66 section 2-7 of the ea82 manual mentioned above.

 

I would backprobe the Green/blue wire (pin 5) at the ECU connector w/key on looking for 12V(or an alternating voltage w/the test mode connectors connnected)

 

My money is on a faulty harness connector under the hood.Page 31 section 2-7 may help.

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Do you mean I should disconnect the solenoid and test the harness leads that plug into the solenoid? Is there a bit more detailed information for how to test for positive/negative voltage?

Is there a secondary connection to the ecu under the steering column that could be checked?

Look at the wiring diagram.  One wire goes from that solenoid straight to the ECU.

 

Find that wire.  Disconnect at the ECU.  Disconnect at the solenoid.  Set your VOM to ohms.  Connect to both ends.  Should be damned near zero ohms.  If it's more than a couple ohms then you have found your problem and can proceed finding the open or high resistive joint and fixing it.

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  • 2 weeks later...

Ok back again. Successfully cleared the code 35 by having an electrician poke around. I don't know if the code was being triggered by a loose connection to the computer or the fact that the green diagnostic wires were plugged in during normal driving. The circuit for the purge solenoid was operating fine.

 

Since my codes were clear and the "check engine" light went off, I took it to get smogged and it failed only for the Nitrous Oxide emissions being too high, about 400 units over the max of 800.  

 

Where to start I could use some help. One smog shop/repair said he would have to start with the EGR system and work his way around replacing components like airflow and O2 sensors, testing the emissions after each replacement. He wasn't able to give me any definite price and estimated that the most expensive replacement would be the catalytic converters that would be around $800 a piece. But then he kept saying I was looking at a total cost of $400-$800+ for the job.

 

My thought is to keep changing the parts I can do my self, I've changed O2 sensors and most things that don't require major dismantling or moving anything that has precise alignments to the engine.

 

Any suggestions of things I can do to bring down NO emissions before taking it to a shop?

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I had one fail for high nitrous.  Bad Catalytic converter.  You can test the cats.  Run the car for a good drive at normal temps.  Measure the temp of the exhaust pipes where it enters and exits the catalytics.  The temp should be something like 100 degrees hotter on the outlet side of each cat.   Find one the same or cooler, there's your problem.

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