Can't get diagnostics socket to work

[SteveHall30]

I've been having a host of problems, but trying to use the diagnostics port isn't helping like it should. This is what I do.
Turn key to off
Put the wire into socket #2
Turn key to on
Press the button (tried all sorts of press durations)
The LED lights up while the button is depressed, but then nothing at all happends, doesn't flash codes, doesn't flash 1-1-1. Absolutly nothing.
Checked the connection to the correct pin on the ECU - fine
Tried a spare ECU - no change.

I'm getting this sudden power-no power jumpyness to the drive, it doesn't stall, but it seems to have two modes.
1) Working normally
2) Under no load, short delay between pressing the pedal and revs rising freely. Under load, press pedal and nothing happens.
The car will just jump back a forth between these two modes with very jerky power as it comes and goes. If you turn off the enginer and start again, it often stays in mode 1 for 30seconds to 2 minutes, but then it'll jump backwards and forwards with a frequency between 0.5 seconds and 10 seconds.

If anyone has any bright ideas why the diagnostic port isn't working, or the engine fault I'd love to hear.

[Nifton]

Hmm, thought i'd replied to this yesterday Sounds like sticking throttle valve or your MAF is coked up or dead maybe. If you want to try a different code reader, I have a spare I can sell ya nice n cheap...

[SteveHall30]

Hi Nifton,
Thanks for the reply. It's hard to explain well how the engine behaves under throttle, but I was able to exclude anything from the throttle, throttle sensor and idle bypass valve from the behaviour.
MAF could have been it, but the switching between high and low power was very fast, so I excluded anything to do with fueling, had to be down to the spark.
The engine never missfired, only high and low power. This got me thinking about ignition timing, because it was just about the only thing that fitted. Bit more thinking and a faulty knock sensor would explain the sudden switching between high and low power as it jumps the ignition advance back and forth.
As a test, I unplugged the knock sensor from the front of the engine, it was a little rough when cold, and when warm it ran smoothly, with perhaps 80-90% power I am used to. Important thing was the power delivery was smooth, no jumping back and forth. So looks like I've found it, new knock sensor will be ordered in due course and I'm looking forward to reliable motoring again :-).

As for diagnostics, I wasn't using a code reader, just the technique where you plug in the wire from the socket and press the button. Still not joy here, but less of an issue now the need is gone.

[glasgowjim]

400 series fault codes

Codes Retrieval

1. Open the diagnostic system's box cover and place the test cable mounted on the side of the box into an appropriate socket.
2. Turn the ignition ON to key position II without starting the engine. Wait about ten seconds.
3. Press the button once and hold it for more than one but less than three seconds.
4. The LED lamp will flash in successive series of three digits followed by a three-second pause. If there are no fault codes stored, it will flash 1-1-1 indicating the system being tested is operating correctly.
5. Count the successive flashes and record the fault code.
6. Press the button again, as described above.
7. Record the fault code. If it is the same as the previous one, then no additional codes are stored. Repeat until all the codes stored are retrieved (often a maximum of three).
8. Turn the ignition OFF and remove the test cable from a socket.

Erasing Fault Codes

1. Repeat step 1 and read all the fault codes again. Do not turn the ignition OFF after read-out.
2. Press and hold the button for more than five seconds, then release it.
3. When the LED lights, press the button again for more than five seconds and release it. When the LED goes off, the memory is cleared.
4. Test that memory is cleared by performing step 1. Code 1-1-1 should be returned.
Note: erasing fault codes on the ABS socket will cause the ABS control to be lit. It will turn off after a test-drive with speed of more than 40 km/h.

Sockets Description

1 – alarm and remote locking system,
2 – fuel system,
3 – ABS,
6 – cruise control,
7 – SRS (airbag).

Hints

Before assuming a fault in any of the systems tested, try to erase fault codes as described above. In my case, open circuit in ABS wiring has initially been signalled with codes 122, 152, 312 and 322. After erasing and performing a test-drive, only code 312 was signalled.

At first, read the codes when the engine is completely cold. Then, go for a longer test-drive and read them all again while the engine is still hot. Some codes (especially these related to lambda-sensor) tend to appear only while the vehicle is driven and short time afterwards.

Socket 1 Alarm and remote locking system
Code:
1-1-1 No error code set
1-1-3 Transmitter to receiver: weak signal
1-1-4 Control Module (CM) faulty
2-1-1 Relay contacts, fuse or ground terminal (locking)
2-1-2 Relay contacts, fuse or ground terminal (unlocking)
2-2-1 Fuse or ground terminal (locking)
2-2-2 Fuse or ground terminal (unlocking)
2-2-3 Codes 2-2-1 and 2-2-2 combined
3-1-2 Siren: internal fault
3-2-1 Siren: power supply
4-1-2 Ultrasonic system: internal fault
4-1-3 Ultrasonic system: one or more sensors faulty
5-1-1 Key switch ground on (> 10 seconds)
5-1-2 Key switch ground off (> 10 seconds)
5-1-3 Locking door with ignition on
5-1-4 Unlocking door with ignition on
5-2-1 Central locking system switch (> 10 seconds locked)
5-2-2 Ultrasonic switch (> 20 seconds locked)
5-3-1 Interior lights, shorting to earth


Socket 2 fuel system
Code:
1-1-1 No error code set
1-1-2 Malfunction in Electronic Control Module
1-1-3 Open circuit in injector wiring
1-2-1 Air pressure sensor: no signal correspondence
1-2-2 Air temperature sensor: no signal or signal faulty
1-2-3 Coolant temperature sensor: no signal or signal faulty
1-3-2 Incorrect battery voltage
1-4-3 Knock sensor: no signal or signal faulty
2-1-2 Oxygen sensor: no signal or signal faulty
2-1-4 Flywheel sensor: signal faulty
2-2-2 System relay coil: no voltage
2-2-3 Idle speed regulating valve: no signal or signal faulty
2-3-1 Adaptive Lambda closed loop control system lean or rich in part–load range
2-3-2 Adaptive Lambda closed loop control system lean or rich at idling speed
2-4-4 Knock sensor: no signal or signal faulty
3-1-1 Speedometer signal: no signal correspondence
3-1-3 Charcoal absorption canister valve: signal faulty
3-4-2 A/C relay signal: signal faulty
3-4-3 Main relay coil: no voltage
4-1-1 Throttle valve sensor: signal faulty

 
Socket 3 ABS
Code: (40 km/h = 25 mph)
1-1-1 No error code set
1-2-1 Left side front wheel sensor: faulty signal at speed less than 40 km/h
1-2-2 Right side front wheel sensor: faulty signal at speed less than 40 km/h
1-2-3 Left side rear wheel sensor: faulty signal at speed less than 40 km/h
1-2-4 Right side rear wheel sensor: faulty signal at speed less than 40 km/h
1-2-5 Signal faulty from at least one sensor for a long period
1-3-5 Control Module (CM) faulty
1-4-1 Faulty pedal sensor: shorted to ground or supply
1-4-2 Faulty stop (brake) lamp switch: open circuit
1-4-3 Control Module (CM) faulty
1-4-4 Brake discs overheated
1-5-1 Left side front wheel sensor: open circuit or short-circuit to battery voltage
1-5-2 Right side front wheel sensor: open circuit or short-circuit to battery voltage
1-5-5 Rear axle sensor: open curcuit or short-circuit to battery voltage
2-1-1 Left side front wheel sensor: no signal or moving off
2-1-2 Right side front wheel sensor: no signal or moving off
2-1-3 Left side rear wheel sensor: no signal or moving off
2-1-4 Right side rear wheel sensor: no signal or moving off
2-1-5 Valve relay: open circuit or short-circuit
2-2-1 Left side front wheel sensor: ABS operation signal missing
2-2-2 Right side front wheel sensor: ABS operation signal missing
2-2-3 Left side rear wheel sensor: ABS operation signal missing
2-2-4 Right side rear wheel sensor: ABS operation signal missing
2-3-1 Left side front wheel sensor: signal missing
2-3-2 Right side front wheel sensor: signal missing
2-3-5 Rear axle sensor: signal missing
3-1-1 Left side front wheel sensor: open circuit or short-circuit
3-1-2 Right side front wheel sensor: open circuit or short-circuit
3-1-3 Left side rear wheel sensor: open circuit or short-circuit
3-1-4 Right side rear wheel sensor: open circuit or short-circuit
3-2-1 Left side front wheel sensor: irregular interference at speeds over 40 km/h
3-2-2 Right side front wheel sensor: irregular interference at speeds over 40 km/h
3-2-3 Left side rear wheel sensor: irregular interference at speeds over 40 km/h
3-2-4 Right side rear wheel sensor: irregular interference at speeds over 40 km/h
4-1-1 Left side front wheel inlet valve: open circuit or short-circuit
4-1-2 Left front return valve: open circuit or short-circuit
4-1-3 Right side front wheel inlet valve: open circuit or short-circuit
4-1-4 Right front return valve: open circuit or short-circuit
4-1-5 Rear valve: open circuit or short-circuit
4-2-1 Rear wheel circuit inlet valve: open circuit or short-circuit
4-2-2 Rear wheel circuit return valve: open circuit or short-circuit
4-2-3 Traction Control System (TRACS) valve: open circuit or short-circuit
4-2-4 Pressure switch for TRACS: faulty or short-circuit
4-4-1 Control Module (CM) faulty
4-4-2 Pump pressure low
4-4-3 Pump motor/relay: electrical or mechanical fault
4-4-4 No power supply to valves in hydraulic unit




Socket 6 cruise control
Code: (40 km/h = 25 mph)
1-1-1 No error code set; speed was higher than 40 km/h
1-1-2 Vehicle Speed Sensor: abnormal signal received
1-2-2 Vehicle speed: 40 km/h not exceeded or no signal
2-1-1 Fault in supply voltage or Control Module
2-1-2 Circuit to vacuum pump or regulator: signal faulty

Important: cruise control diagnostics must be done immediately after the test drive. Do not turn the engine off! Codes will not be saved in memory if you do.

Socket 7 SRS (airbag)
Code:
1-1-1 No error code set
1-1-2 Internal fault in the sensor unit
1-2-7 SRS warning lamp: open circuit or short-circuit
2-1-1 Steering wheel module: short-circuit in wiring
2-1-2 Steering wheel module: open circuit in wiring
2-1-3 Steering wheel module: short-circuit to the ground
2-1-4 Steering wheel module: short-circuit to +12V
2-2-1 Passenger module: short-circuit in wiring
2-2-2 Passenger module: open circuit in wiring
2-2-3 Passenger module: short-circuit to the ground
2-2-4 Passenger module: short-circuit to +12V
2-3-1 Left seat belt tensioner: short-circuit in wiring
2-3-2 Left seat belt tensioner: open circuit in wiring
2-3-3 Left seat belt tensioner: short-circuit to the ground
2-3-4 Left seat belt tensioner: short-circuit to +12V
2-4-1 Right seat belt tensioner: short-circuit in wiring
2-4-2 Right seat belt tensioner: open circuit in wiring
2-4-3 Right seat belt tensioner: short-circuit to the ground
2-4-4 Right seat belt tensioner: short-circuit to +12V
(no code) SRS warning lamp in the instrument panel does not light
(no code) Fault in diagnostic output



Thanks to: http://www.am.torun.pl/~ja/volvo/dia...c-system.shtml

well you did ask :hopping: :hopping: :hopping:[/quote]

[vicpool]

This may or may not be of some help

When I had a new central locking module fitted at the garage and new remotes which had to be programmed the mechanic could not get the diagnostic led to work (necessary for this operation) as in yours he could get no response. He then said that often with little use the connections in the diagnostic connector don't make proper contact. He then flooded the connector with switch cleaner which then did the trick and the diagnostics codes came to life. You could try this.

[Nifton]

I've got a box of knock sensors as well. Can flog you one if you want? Glad you got to the bottom of it mate. That's why I love the 400 series, you never need a mechanic! Btw you will need a torque wrench to fit the new knock sensor. They are v sensitive if on too tight!

[SteveHall30]

Looks like the problem came back. A real head scratcher.
Thanks for the info on the diagnostics port vicpool. I didn't notice the bit didn't look like the best electrical conductors and tried twisting the jumper wire connector to scratch the surface, I'll have a try some other cleaning methods to get a real connection.

[SteveHall30]

Well, cleaned the contacts: No Good.
Got some wire and a multimeter and confirmed direct connection between the diagnostics port ground and the correct pin in the ECU, still nothing.

[Clan]

Originally Posted by SteveHall30

Well, cleaned the contacts: No Good.
Got some wire and a multimeter and confirmed direct connection between the diagnostics port ground and the correct pin in the ECU, still nothing.

can you get it to work in any of the other active sockets ?

[SteveHall30]

No, nothing from anything. But I've just found this:
http://www.volvo-forums.com/t20287-diagnostic-codes.htm
Which has the line:
"If you have an immobiliser you have to unlock on the fob before you turn the ignition on otherwise you will get nothing from diagnostics sockets"
Considering that the key was lost, the car was taken to Volvo who couldn't program the fob (But still charged £140 to try). I've re-wired the 4 relays the immobiliser messes with so the car can start and drive, but that brings me to my first post.