check engine light...

stecz

Well-known member
Sep 4, 2004
88
0
My check engine light is on, when I checked the codes last, it had two codes that referred to the Air/Fuel Ratio. That seems like it's probably the oxygen sensors. Does anyone have a technique for testing the O2 sensors? I would like to test them before I jump and replace all 4 of them.... (98 Disco)

Any other ideas?

Thanks.
 
R

roverfixer27025

Guest
"I'm the boss, need the info..."

What make, year model, mileage, & the codes?

Get me that and I'll try to help you out.
 
On a 98 disco, the oxygen sensors can be tested with an oscilloscope and looking at the signal output. Also, the heater circuit can be tested by looking for presence/absence of power at the wiring harness, and looking for contiuinty through the heater circuit of the sensor itself.

Whether or not the sensors are reponsible for your codes remains to be seen. I have seen few cases where the sensors were actually at fault.
 

Joey

Well-known member
Apr 19, 2004
976
0
Liberty Township, Ohio
Also, if it is talking about Air/Fuel, then it could just be the MAF needs cleaned.

But since you haven't provided the codes, it is hard to tell.
 

stecz

Well-known member
Sep 4, 2004
88
0
sorry, it's a 98 with 80000 miles. I'll go buy a code reader and post the codes (I borrowed one the last time). The idea with the MAF is what I was looking for. I'll clean that off for starters and go from there...

What parts place will read your codes for you for free?

I'm unemployed right now, so I hate to spend $77 on a code reader at the moment. (that may change tomorrow...)

John S.
 

stecz

Well-known member
Sep 4, 2004
88
0
I just called advance autoparts and they will check the codes for you...

I know it's getting 2 separate codes that are the same description, so I assumed it was a left bank/right bank thing.

Can you just spray fuel injection cleaner throught the MAF?

I was going to do that and spray off the throttle body, the butterfly is not clean, but it doesn't look like carbon buildup (it's not thick). But that seams like a place to start. I also will get new spark plugs and replace those. I'll then clear the codes and see if I get them again...

Thanks.
 

Joey

Well-known member
Apr 19, 2004
976
0
Liberty Township, Ohio
Cleaning the MAF (this is what I have been told on this site) is to clean them with some electrical contact cleaner is the best way. Then let dry completely prior to reinstall
 

stecz

Well-known member
Sep 4, 2004
88
0
I had the codes checked (and reset)... the only code was:

P1193
Manufacurer Control. <- the code reader spelled Manufacturer wrong :)
Fuel Air Metering


I bought some "throttle body cleaner" to clean off the butterfly and MAF (is that ok?) and spark plugs to see if that clears things up.

Any other ideas?
 

stecz

Well-known member
Sep 4, 2004
88
0
I cleaned the throttle body with throttle body cleaner and the MAF sensor with contact cleaner... But, the light came on. In the course of fixing that, I noticed that the breather hose connecting the valve cover to the throttle body was in bad shape. I was going to go and get a piece of hose to fix it, but the check engine light came back on, so I wrapped it with duct tape temporarily. Now, I need to go check the codes. The hose appears to go into the throttle body before the butterfly, so it's not technically a vaccuum leak, but it could cause confusion this the MAF sensor and throw the code...


I need to go to Advance and get the codes read again.
 

stecz

Well-known member
Sep 4, 2004
88
0
Darn, I cleaned the MAF and the throttle body, I also replaced the breather hose, and the code got set again... Any other ideas?