Hello!

Coming from a 240, I just recently picked up at 1990 Volvo 740 16-Valve with about 105k documented miles. The TB on the car was just replaced, and thought I was ready to go, but over the last few hundred miles I'm getting an intermittent check engine light.

I'm getting codes 2-3-2 and 2-4-1 along with the check engine light. Once the codes are cleared, they come back about 100 miles later. The car seems to drive well, but takes about 2-3 seconds to crank. I might be in need of a new fuel pump or relay soon. If left for a few days, the car idles a bit rough when cold, but drives well afterwards. Before I start pulling and testing parts, are these codes together indicative of a common problem? I'm looking for some advice about where to start first.

Thanks in advance!

 

Have a look at those:

Engine and OBD Diagnostic Codes

Maybe all you need is a new O2 sensor?

 

Thanks for the prompt response. That was my thought as well. I will pull the sensor to test them and update!

 

Waynesford, any news in this issue?

I have the same codes and symptoms in a '90 760 turbo .
The Check Engine light and codes come intermittently as well.

Been wrestling with the solution for months.

Your response is greatly appreciated!

Thank you.

 

waynesford hasn't posted since the 3 posts in this thread, 4 years ago.

per https://www.volvoclub.org.uk/faq/EngineOBDCodes.html

code 2-4-1 is an EGR error. Assuming the EGR control valve works, and the EGR actuator holds a vacuum, its most likely that this is because the EGR pipe is plugged with carbonized flug where it goes into the intake manifold.

2-3-2 basically says the O2 sensor thinks things are out of range. sadly, it doesn't say if its too rich or too lean at idle, it could be either, so you need to figure out which. 2-3-2 could mean an injector is leaking, or fuel pressure is too low or high, or intake manifold air leaks, lots of things.

 

Hello, my name is David, i’m from the north of Spain.
I have a ‘90 Volvo 740 SW. B230FB.
I need some help! The car has the 2-3-2 default code.
i have changed a lot of parts, but i can’t discover the problem.
I bought new: fuel pump in tank, fuel filter, main fuel pump, fuel injectors, fuel pressure regulator, spark plugs, complete exhaust with catalyse converter, lambd sond.
All new and original Bosch.
But i can’t find the problem.
The car takes a while to start. Then, it works normaly but on highway in 5 gear and in little steep climbs I notice that it lacks power.
Sometimes when the car stops, the engine gets a little accelerated and then stabilizes.

I need any idea to look for the problem.

Thank you very much for any comments and help

 

start wth the simple - check for intake air leaks. Vacuum lines, vacuum tree, intake manifold, exhaust manifold. You may need to do a smoke test as the vacuum lines may be hard to trace.

 

2-3-2 is not the default code, 1-1-1 is. 2-3-2 indicates the lambda (fuel trim) is either too lean or too rich at idle. thats a lot of random parts to throw at it without having diagnosed they were actually at fault and bad. new parts are often poorer quality than the originals.

anyways, I think I would do a simple OXS test... there's two connectors, find the one that has 1 pin (the other connector has 2 wires and is for the heater, ignore that), wrap a single thin strand of copper wire around the pin and put that connector back together, with this thin wire hanging out a few inches. connect a volt meter set for a low DC volt range to that copper wire and a handy ground. start the engine, let it warm up a bit. ideally, the voltage you read will be swinging back and forth every few seconds between a lower value around 0.1-0.3V and a higher value around 0.7-0.9V. the actual voltages don't matter, just that its swinging from less than 0.5 to more than 0.5 and back. if these swings are happening slowly, like 10 seconds or longer, your O2 sensor is old or defective.

if its pegged at the higher value, you're running too rich and if its pegged at the lower value, you're running too lean. air leaks in the intake after the MAF are a common cause of too lean. excess fuel pressure is a common cause of too rich.

more info on this test here, https://www.volvoclub.org.uk/faq/Eng...nsor_Diagnosis

 

i have checked the vacuum lines, and i have installed some new lines: inlet manifold to brake booster and to the interior compartment.
and i checked the backflow valves. They works well.

i’m going crazy!!!

 

The O2 sensor is new too. The original Bosch.

I detected the engine oil dirty with 1000kms.
is possible a default in the valves seals?
i checked the cylinders compression and it is OK. The Haynes Manual said a good compression between 9 and 11 bar.
i have 10,5 in the 4 cylinders.

 

Could be your air mass meter. When they go bad they tend to throw those two codes. They are rather expensive to replace so I tend to pick spares from the junkyard and keep them on hand for these diagnostic purposes. If you have access to a spare, replace it and reset the codes and see if they come back.

 

make sure the air mass meter aka MAF you score from the junkyard has the same Bosch part number, or same pin count, or whatever. basically has to be a 1989+ bosch 240/740/940, or a 1990+ turbo... and not one of the oddball LH 3.1 units, they have a different pin count on the connector. older cars were LH 2.2 and also have a different pin count.