94 960 ---Ignition Problem

[billofdurham]

1 indicates infinite resistance. Using the 2,000 ohms scale a reading of 1,900 is near enough infinite.

As you have an infinite reading on the first test you don't need to check between terminal 4 and ECM 25. Instead check between terminal 4 and the positive pole of the battery with the ignition ON. You should get battery voltage which indicates the problem is a bad connector in the ECM and/or the MAF connector.

Bill.

[Kappy5003]

Bill the saga continues
I did a voltage test between #4 and postive terminal
Ignition off- Battery voltage ----12.6
Ignition on - 11.8

I did this the ther day after cleaning the terminal at ECU and got battery voltage ignition on & off.

Interestingly yesterday removed all codes started car everything ok went for a short drive off about 1 km which about all it seems to take before code seems to return, Hot wire code felt a slight flutter.

Returning to carport noticed idle in gear was fluctuating up to around 1000rpm down as low as near stall. Dash lights would flutter.
With gear in park, idle would flucutate between 500 & 1000rpm.
Give a short rev and would be stable for a few secods then would fluctuate again.

Turn engine off check codes yep 3.2.2 hot wire.

Is it possible that the ECU is iffy or could an aspect of the MAF be faulty.

[billofdurham]

Having battery voltage on that check indicates that there is a bad connection in the ECU and/or the MAF sensor connector.

My Volvo contact tells me that the ECU doesn't often fail without some 'human help' aggravating the situation.

In a perfect world the resistance across terminals, contacts or leads should be 0 ohms. However, there is always some resistance due to oxidation. When that resistance reaches a certain level it will cause a malfunction.

To ensure there is no, or very little, oxidation in the MAF connector spray the pins/sockets with a rust solvent spray, allow it some time to do its stuff and blow clean with compressed air. Grease the female terminals with a dielectric grease making sure all of the sockets are filled. Don't fill the rubber boot with the grease. This procedure is best done with the ignition off and the negative battery lead disconnected.

You can do the same for the ECU but for this you must wait at least 4 minutes after switching off the ignition or the cooling fan has stopped before removing the ECU from the car. This allows the main relay to interrupt the supply to the ECU.

Bill.

[Kappy5003]

Hi Bill
Well what an interesting exercise.

I set about cleaning every connection, male and female, I did note there was still some residue grease from whover put it there.

After a thorough clean everything nice and shiny all reconnected turn of the key fires up purrs like a kitten. I might add connected dry.

Voltage test ign off Battery voltage---12.5 ignition on 11.3????????

Go for the common short drive return still running smoothly, although along the way felt the little hiccup that code returned although still smooth.

Check codes yes 3.2.2.

Next I apply the grease as suggested start car immediately runs runs rough erratic idle etc. Turn off clean all connection again recoonect with no grease and when starting again smooth, short drive etc, code still there but drives OK.

What is likely long term scenerio of driving with this code??????

On doing some research I discover suggestion that this dielectric grease shouldn't be used on connections, so somewhat confused ??????
I am a bit lost don't know how to eliminate voltage reading with ignition on Between MAF#4and positive????

Cheers

[billofdurham]

First, my apologies, I should have said an anti-oxidant grease. I use a silicon spray grease which is conductive but waterproof. To get it fully into the female sockets I spray the grease on and the push it home with an old male socket.

I have done more research into this and can't understand why you are getting 12 volts with the ignition off. My friendly Volvo man is baffled and my very friendly auto-electrician is totally baffled.

One point we did agree on, however, is that you shouldn't get code 3-2-2 whilst you are driving. This code is set if the voltage passed to the hot wire to clean it, after switch off, drops below 2.5 volts. It should be 4 volts but will still burn off as low as 2.6 volts.

One thing I did learn about erasing fault codes was, "Erasing is only possible after all Diagnostic Trouble Codes have been read at least once and the first stored at least twice". As the check engine light doesn't illuminate for 3-2-2 you have no visual reference that the code has been deleted. That begs the question are you reading the code twice before erasing it? Probably, but it is a possibility for that code always popping up.

The other thing I found was, "All faults in the self diagnosis system are reversible, with the exception of KS signals. In other words if an absent or faulty signal becomes correct again the ECM takes this into account as soon as the fault disappears instead of operating in limp home mode. However, the code remains in the memory". That should answer your query about long term driving with the code.

We are both on a learning curve with this one.

Bill.

[Kappy5003]

Greeting for the festive season.

Update of ongoing issue.

Seems as though my ignition is is solved with new battery terminals and new ignition switch.

However still have this hotwire code, guess it pops up after ignition is turned off.

So over the last week Ihaving been driving the girl around, I say girl cos unpredictable.

Driven into town a number of times, 50k round trip and some short hops around 2-4k round trip generally drive ok apart from some slightly erritic idle fluctuates between 500 & 1200rpm, also noticed puffs of black and dark grey smoke.

Well on Christmas eve up pops checl engine warning light..and on checking codes......
old faithful 3-2-2 hotwire
and 5-1-2 as discovered in earlier post 5-1-2 is short term fuel trim - lower limit. It is probably linked to the others as diagnosis involves testing the MAF.
As I have been getting this hotwire code for some time and the MAF is an el cheepo is it possible the MAF is iffy even though no other related codes...
Of course my after market immobiliser has a mind of its own, we don't need a second immobiliser in WA anyway main purpose is for remote central locking.

Could my grounding issue (now resolved) have had an impact on my ECU and or MAF or even the immobiliser???????

I might add even with Check engine warning light still driving Ok

[billofdurham]

5-1-2 can be set by the MAF. A further check is the 53 pin connector in the left wheel arch. With the ignition off and the MAF disconnected check #19 in that for oxidation. After that put an ohmmeter between MAF connector terminal 1 and earth. You should get 0 ohms or near enough.

Bill.

[Kappy5003]

5-1-2 can be set by the MAF. A further check is the 53 pin connector in the left wheel arch. With the ignition off and the MAF disconnected check #19 in that for oxidation. After that put an ohmmeter between MAF connector terminal 1 and earth. You should get 0 ohms or near enough.

Bill.

Hi Bill
Merry Xmas
Excuse my ignorance, but I'm confused with the 53 pin connector in the left wheel arch.
I have thoroghly cleaned all the connections to the ECU. The only thing I see on the left front wheel arch is a fuse box and nearby the diagnostic unit.
Is it the wires coming into the fuse box?

Cheers
Wayne

[billofdurham]

Wayne,

You should have a connector in the left wheel arch if you have a 1994 or earlier model:

1994 960 53 pin connector left wheel arch.pdf

(257.86 KiB) Downloaded 210 times

If you have been deceiving us and have a 1995 or later model the connector is in the engine compartment fuse box:

1995 960 53 pin connector fuse box.pdf

(401.13 KiB) Downloaded 214 times

Volvo model years change September/October so you may have a '94 car which is a '95 model. If it is this one you are looking for pin #13 in section E.

Bill.