ECU problems

evevolvo · Post by **evevolvo** » 08 Jun 2009, 11:27

my 92 740 will not idle runs too lean have changed mass air flow controller engine check light on but readout is 1 1 1. Have cheked 12voltsdc at ECU connector and grounds are good. should i change the ECU and what is the procedure to do so? (is it just plug and play?)

Ron Richison · Post by **Ron Richison** » 08 Jun 2009, 20:21

are you sure it's your ecu?
I have idle problems and a lean run like yours. I have chased it with many hours of work and over $600 in parts. Finally, the volvo dealership told me it was either the air flow sensor or the ecu. Since I've replaced the airflow sensor, I'm left with the ecu. I'm a little hesitant though, they are very expensive.
Did a tech diagnose this for you or are you just trying to fix it yourself like I did?
Ron

evevolvo · Post by **evevolvo** » 09 Jun 2009, 11:05

[/quote]I have had a mechanic look at the problem and thats when we changed the mass air flow sensor. He suggested the next thing would be the ECU. The mechanic is not specifically a volvo specialist so I hate to spend money on his time when I can do the same thing (guess). The ECU cost ~400$ and seems simple to change although with computer devices thier must be a procedure to install and do they need to be programed or are they plug and play? There is not much to the engine it is only a four cylinder and should be simple right. The only way to fix it is the R and R (remove and replace) method although there is a trouble code that i am not getting that specifically says bad ECU which i am not getting

Ron Richison wrote:are you sure it's your ecu?
I have idle problems and a lean run like yours. I have chased it with many hours of work and over $600 in parts. Finally, the volvo dealership told me it was either the air flow sensor or the ecu. Since I've replaced the airflow sensor, I'm left with the ecu. I'm a little hesitant though, they are very expensive.
Did a tech diagnose this for you or are you just trying to fix it yourself like I did?
Ron

Ron Richison · Post by **Ron Richison** » 09 Jun 2009, 11:36

I got the exact same advice from a Volvo tech AMM or ECU, I re[placed the AMM and it's the same. The ECU is plug and play. Make sure your battery is disconnected first though. That's key.
I'm trying to find a used ECU on the internet but am striking out finding the same number as the one that came out of mine.
Let's stay in touch and see if we can get both these cars running.
I'll let you know what I find out by Wed.

evevolvo · Post by **evevolvo** » 09 Jun 2009, 15:55

Ron Richison wrote:I got the exact same advice from a Volvo tech AMM or ECU, I re[placed the AMM and it's the same. The ECU is plug and play. Make sure your battery is disconnected first though. That's key.
I'm trying to find a used ECU on the internet but am striking out finding the same number as the one that came out of mine.
Let's stay in touch and see if we can get both these cars running.
I'll let you know what I find out by Wed.

i am in the process of getting the number off my ECU if you could give me yours maybe they match and i might be of help locating one and could give you contact info and cost, thier is a auto recycler who said they have them for 350$ if the part# matches. I am in the sacramento area.