How to use the On-Board Diagnostic (OBD) unit.

[dee23]

I cant download instructions for using OBD . I have 1991 740 GL n0n turbo. I think I ve found the box, It has a push button and a led light bulb with a few open sockets, its a small box, about 3 inches by inch and a half. now if I have the correct box, can some one tell me how to use it and read it. I'll find what the codes mean later. I need to know what and how to use it first. All advice would be very appreciated.

[billofdurham]

I posted a link yesterday to another site in your thread in the main part of the forum. Can you not download that one either?

Bill.

[dedrums]

hey dee i went and picked up the chilton book for our car it explains how to read this cool tool i have a 92 740 wagon and its on the drivers side infront of the strut theres 2 black boxes.its cool i was just going to ask bill what does steady flash mean cause it sounds like he knows his volvos

[dedrums]

hey bill found the codes pushed the button once got 232= lamda control too lean but when i pushed it twice got a reapeted flashand pushed it 3 times got flashes 3 flashes chilton doesnt cover flashes do you know what this is thanks alot

[dee23]

great , I will check my car. I dont know how to use it though. does the key have to be on? how many times do I push the button? How do I do the counting of flashes? I wish I knew more about this, But its completely new to me. I just replaced cold start injector and dont even know if that was the problem. I hope I can find out soon how to use the OBD. thanks for your help

[kit44]

Hi Bill
I have a 1997 940 classic LPT and I have just found that the diagnostic socket is located inside and at the base of the centre armrest locker (instead of on the side of the centre console) there is no OBD unit on the wheel arch, Volvo must have removed it for this year intending to use the OBD11 system but not using compatible scanner software. Although Volvo say that this car is OBD11 compliant, I have tried 4 scanners in this OBD11 connector and none of them work. It seems that this car is not OBD11 compliant. The vehicle was manufactured in 1996 and first registered in 1997, this was at the end of the 940 factory run and may have incorporated parts of the V70. I have made up a diognoistic test lead with a switch and a LED and found that the fault codes are 1-1-1 (no fault for the fuel system) and 1-4-4 (ECM load signal) for the ignition system.

My original problem was the Lambda sond light came on and the engine stalled and temporarily refused to start. I fixed an exhaust manifold problem but the lambda sond light remained lit presumably with the fault codes saved. I reset it by removing the battery leads, shorting out the positive and negative car leads (to short out any capacitance in the system) and then reconnected the battery. The lambda sond light then extinguished automatically after start up.

I have used this car after resetting the lambda light but the fault re-occurrs a couple of days later with the 1-4-4 fault code. The Haynes manual doesn't appear to mention the ECM (is this Electronic Control Module or Engine Control Module?)
Have you any idea where the ECM is situated? and where does the Load signal come from?

[billofdurham]

The '96/'97 is OBD11 compliant but, for some reason, the scanners we can buy are not compatible with the Volvo system. I have the same problem with my '95 registered but '96 model 850. I could set up a shop selling the OBD scanners I have bought and found to be useless.

I use the same kit as you and it is adequate for my purposes.

The Lambda Sond light is the Check Engine Light (CEL) which does come on when one or more fault codes are stored.

The ECM is the Engine Control Module. Code 1-4-4 on the ignition side can be set by an open circuit or short circuit to earth in the cable between the LH 2.4 module (fuel supply) terminal 25 and the EZ 116K module (ignition) terminal 8. The attached shows how to check.

940 (UK) ECM check.pdf

(369.86 KiB) Downloaded 525 times

The ECM is behind the right hand side kick panel and the ignition control module is in the left hand foot well.

Bill.

[kit44]

Hi Bill
Many thanks for your reply, I have now changed the Fuel Injection (radio suppression) relay found hidden behind the power steering resoirvoir to negate the "dodgy relay" syndrome, but this does not seem to help the situastion (the car still cuts out after 200 yards but starts again after leaving it for a few minuted, again showing the lambda light - biggest problem is no power steering and no brakes when the engine stalls) I will try your ECM checks but cannot seem to find how to remove the side trim kick panels in the footwell. Any help would be appreciated.
Thanks.

[ureneighbor]

hello, I'm new and I'm getting an 88 240 DL wagon today. I have question though, I can't find the OBD? Does this model not carry one? or did I not look hard enough.

thanks,


Mr. Roger's

[kit44]

I hope the following may be of use to your readers, it is my account of the problem and the remedy.

1997 Volvo 2.3 petrol LPT Classic 98,000 miles Problems with the OBD.
The following problem started about three weeks ago, no previous problems.
The vehicle will start and after a couple of hundred yards, the Lambda light illuminates along with all of the other lights (as though the ignition has just been switched on) and the engine cuts out completely and immediately. The engine will not restart immediately but will start after a couple of minutes. The Lambda light then stays on and the car appears to be able to be driven normally.
I have replaced the fuel supply relay under the bonnet (nearside front wing panel behind the Power steering oil tank) as I understand that this relay (sometimes called the radio suppression relay) powers the fuel injectors.
I have also checked out each fuse in turn but they all appear to be OK.
There is no on board diagnostic box under the bonnet on this 940 (although there are a couple of leads that probably used to be the diagnostic leads) and the actual OBD11 socket is located inside the centre arm rest box (as on later V70 cars). According to Volvo this socket is OBD11 compliant but modern scanners cannot be used on it as the Volvo OBD system is not compatible with modern scanners as the protocol used by Volvo is only able to be read by the Volvo diagnostic scanners. I have tried four different scanners all to no avail even though the scanner manufacturers say they are compatible, I can assure you that the scanners are not compatible with Volvo protocol.
I made up a test box with a switch and a LED according to Volvo owners forum information and obtained the following codes, 1-1-1 (no fault found) on the fuel setting and 1-4-4 (ECM load signal/ Fuel system ECU Load signal) on the ignition setting, this code led me to the fuel relay (radio suppression relay) which I changed. Fault still there. Access to the location of the ECU’s is not clear and indeed I have not yet found them although I understand they may be behind the internal side kick panel trim behind the radio.
Having reset the lambda light by removal of the battery lead, The car started and could be driven for about 200 yards before cutting out again. The coil leads were then checked for voltage, there was none both with the ignition on and off. The battery was then disconnected and the coil leads were then removed and cleaned and the voltage checked again, 12 volts on both terminals (probably because the lambda light had been reset by disconnecting the battery). When the engine cuts out it appears that the voltage to the coil is removed, this would reinforce the cause as ignition based, as there is no stuttering just a complete switch off.
The fault now appears to be that the engine cuts out when the volts to the coil are removed. What causes the volts to be removed?
Information on Engine load is supplied to the Ignition Control Module from the Fuel Injection System Control Unit. The load being determined by the quantity of air being drawn into the engine through the Air Mass Meter The Control Unit sends a signal to the Power Stage which is an electronic switch controlling the current to the Ignition Coil primary windings. Note that the diagnostic code gives code 1-4-4 which is “fuel system ECU load Signal”. (extract from Haynes Manual).

Since writing this account of the problems I had been having with the Volvo 940, I have identified the problem as being an open circuit on the coil of the Fuel Injection relay, Volvo part 898151 (made in Germany) part number 35 23 608. The relay is located behind the ashtray and requires the removal of the radio. This radio removal took the best part of a day to work out how to remove it. It seems that there are two thin cutouts on either side of the radio where a couple of small, long and thin screwdrivers are required to ease the clips that hold the radio in place. There is also a clip at the top of the radio that holds the radio in place. (Best of luck with this operation)
On replacing the relay with a unit bought for about £18 from the internet, the past problems of the vehicle battery going dead after four or five days of non use disappeared, so there must have been a current drain through the faulty relay.