CEL OBD I Questions

[A_DuB]

Got a couple questions regarding OBD I and a CEL. I know that the green connectors are for the D-check mode and black are for U-check mode. But besides that what is the actual differences in them. In D-check are your suppose to drive the car or start it and when will it give me the codes.

 

As far as U-check mode goes do I disregard the first blinks that I get and go with the steady blinking code. The reason I ask is because the fist code I get is 22 (knock sensor) but after that it just keeps repeating 13 (Cam angle sensor). Should I just go ahead and check the resistance on the camshaft sensor and does the car need to be running when I do this check?

[Legacy777]

I don't think you're reading the codes properly. It will repeat ALL the codes, not just the last or first one.

 

D-check is a more "active" diagnostic mode. You must follow the instructions on my site and....yes you have to drive it around. The ECU will pull readings from the sensors to make sure they're operating properly.

 

U-check just checks for previous codes in the ECU.

[A_DuB]

So you don't think I'm reading the codes properly.

 

Let me get this striaght should the OBD quit blinking the CEL after giving me the codes, or does it repeate all the codes stored in its memory till it is shut off?

 

I LL just explain what I did to get to the point inwitch I am in.

 

Step one: Go outside open car door.

 

Step two: Look under drivers side of dash pannel and pulg black connectors together for U-check mode.

 

Step three: Put key in the ignition and turn to on position (not running)

 

Step Four: CEL goes Blink... Blink... Blink, Blink, Blink... Blink, Blink, Blink, Blink... Blink, Blink, Blink, Blink... Blink, Blink, Blink,

 

Blink... = Long blink of CEL

Blink, = Short Blink of CEL

 

Sorry Josh couldn't find D-check instructions on your site.

[Legacy777]

Let me get this striaght should the OBD quit blinking the CEL after giving me the codes, or does it repeate all the codes stored in its memory till it is shut off?

 

Yes the computer will repeat ALL the codes stored in its memory until the key is switched off.

 

So from your post, I'd say you have the following codes

 

code 22

code 13

 

The computer should repeat all the codes, and not just one. I don't know what to tell you. Try pulling the EGI/TCU fuse, to erase the stored codes. Drive the car and see if any come back

 

D-check

 

If you have done the above procedure, you will likely wonder what the green T-shaped connectors are for. These are for a more active code reading procedure called D-check mode in the Subaru manuals. To perform D-check, start with both connectors disconnected, start the engine, allow it to warm up, then turn it off. Next, connect the test mode connectors (green T-shape). Turn ignition to ON position without turning on engine. At this point if the check engine light does not come on, it is faulty and must be fixed before continuing. Depress accelerator pedal to floor, return to half throttle and hold for two seconds, then release. Start the engine. Now the light can blink in two different ways. If everything checks out so far, it will blink to indicate a number 01, 02, 03, 04, 05, 06, 07, or 08. If a problem is already detected, it will blink according to the chart below. Either way, your next step will be to drive the car with the test mode connectors connected. You must drive over 7 mph for at least one minute, and shift up to 4th gear if you have a manual tranny. Now, either you will discover any trouble codes, or if you have none it will blink at a steady rate.

[A_DuB]

Well I took out the EGI Fuse, let the car sit for about half an hour and did U-check diagnostic again. This time the codes did repeat two long two short, two long three short, two long two short, two long three short.

So I guess that the Knock sensor should be checked out, but could the MAF sensor code show up because of a broken vacuum leak?

Took the EGI fuse back out and put it right back in and tried to do D-check. When I turned over the car it blinked 5 times real quick repeatedly and by the time I was finished driving around it was just blinking steadily. But I had fun getting up to 50 in a 35 since I don't live right by a freeway :cool: When I

depress accelerator pedal to floor, return to half throttle and hold for two seconds, then release.

should I have had the clutch in?

[Legacy777]

When you have the clutch in shouldn't really matter.

 

A vacuum leak shouldn't cause the MAF sensor code. If it's still showing up, you probably have a problem with it.

[A_DuB]

Pulled the EGI Fuse again and let the car sit overnight, got the same codes this morning 22 Knock sensor, and 23 MAF sensor. The knock sensor was a pain to find and even harder to get the connector apart. When the book says there should be no continuity they mean none what so ever, Right? It had a little continuity so I guess ill have to get a new knock sensor and gaskets for the intake manifold, unless I can get to it without taking out the manifold.

 

The MAF still had battery voltage and I don't have a SCAN tool to check its Grams per second. Does my Haynes book mean a diagnostic Scanner when they refer to a "Scan tool?" And is there any other way to check to see if the MAF sensor is working correctly. I took out the snorkel a while back ago that wouldn't cause the sensor to malfunction would it?

[Legacy777]

You probably have the old style knock sensor. It should be replaced. The newer ones aren't prone to crack like the old ones.

 

As for testing the MAF, here's scans from the FSM

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/MAF_testing1.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/MAF_testing2.jpg