V70 '98 crank, no start. Out of ideas [Fenix, IMMO3]

MotorTheresa · Post by **MotorTheresa** » 11 Jul 2024, 08:13

Good afternoon everyone. It's my first post here.
Bought a 1998 V70 10V manual in may. Car ran fine for 2 weeks. Lambda light was on for some time with the pre owner already when I bought it. Occasional starter hickup (3 times or so, like starter hitting the flywheel tooth to tooth) but car did what it should.
*This is going to be a long-read, sorry. Wanna make sure no detail is left out*
One morning I got crank but no start. Engine runs for 2-3 seconds then quits. Will accept revs even before shutting. Roadside assistance approved of my basic diagnosis (fuel, air, ignition) , connected to OBD and called the ECM shot (no comm to ECU).
Same behavior with both keys. I've replaced Antenna ring upon suggestion (Volvo part via skandix) - no change.
Plugs are new OEM, disty cap cleaned, wires good, air filter element new, all fuses OK, fuel pump relais OK, used spare pump, also spare cam- and crankshaft pos. Sensors.
Checked connectors, went through troubleshooting paths from DELPHI diagnosis tool. Delphi was unable to communicate with the ECU. Also Delphi did not confirm an active Immo. Fabbed OBDII reader acc. https://volvo-turbo.de/obd-ii.html but LED stays dark.
ECM and connector look clean. Vis-Check of ECM internals was OK. When I had the ECM hooked up to fly-lead connection (not inside the box) the car suddenly recovered! Started 10 times and ran well until I've reassembled all into the box again. It's all crank, no start since then. The LED on top of the dash is never on. Pre owner did not recall seeing it on ever neither. Vehicle shows same pattern with Immo3 box assembled and disconnected. I don't have a key fob but receiver 4/19 is installed on top of dash. Operating the doors with key. Central Locking works via key, does not really work from the inside.

I am measuring voltages at the ECM terminal now to see if something's missing or off. My baseline is this pinout:https://charm.li/Volvo/1998/V70%20L5-2. ... %20Charts/. Not sure if this is Fenix or M4.4 though.

I am struggling to part out a fine 220k km V70 in good condition but coming to a dead end here. Open for any suggestions, diagrams etc.

Thank you for reading this far!
-Chris

yanga001 · Post by **yanga001** » 11 Jul 2024, 11:52

The 98 V70 computers are interchangeable, although the 10V is quite a bit more rare if i recall. I had issues with the manual climate control system having cold solder joints and malfunctioning. Reflowing the connector fixed the issue.
You could carefully reflow the ECM connector and see if that helps? It might be that the pressure of the connector is causing a bad or intermittent connection on the board. For reference, when my MCC was going out, applying pressure to the face of the module would allow the AC to engage on occasion. Once reflowed, it engaged normally.

You've replaced every part that normally is associated with hard or rough starts.

MotorTheresa · Post by **MotorTheresa** » 12 Jul 2024, 08:59

Just finished reflowing the Connector pins to the PCB.
Will let you know if this worked or will change something.

Btw. How does the Immo work? Will it cut supply to the ECM or will the ECM cut supply to end points ignitor, fuel pump, injectors etc.?

Is there a Pin in the ECM socket which can be linked to the Immo ?

Reaching for any straw here. Vehicle is dead since weeks now.

Thank you!

jmartin919 · Post by **jmartin919** » 12 Jul 2024, 10:19

Depends on your engine management system:
Fenix 5.2 and Motronic 4.3 connect pin 2 on immobolizer to pin 5 on ECM plus pin 4 of IMMO to 36 on the ECM in the case of Motronic 4.3; Motronic 4.4 and MSA 15.7 connects pin 4 of IMMO to 36 of ECM. I would think the ECM controls everything not the IMMO.
Edit: to complete the data, '99 with the MSA 15.8 and '2000 with ME7- pin 4 of IMMO goes to pin 22 of ECM.

jmartin919 · Post by **jmartin919** » 12 Jul 2024, 10:22

Ah, I see you have the Fenix so pin 2 on IMMO connects to pin 5 on ECM.

Post by **Clemens** » 12 Jul 2024, 15:29

shout-out @xanthefin
He might be able to help

MotorTheresa · Post by **MotorTheresa** » 12 Jul 2024, 15:48

@yanga001 Reflowing the ECM did not change the issue unfortunately, but didn't hurt either I guess;)
I have run tests with 12V bypasses to pump and Ignitor today but vehicle cuts out still.
Checked in/out voltages at the IMMO3 and noticed it does not react or changes values with the key input.
Thank you for super valuable feedback on the Immo/ECM pin @jmartin919! Is that pin B05 at the ECM as shown here?
https://charm.li/Volvo/1999/V70%20L5-2. ... %20System/ ? Would the IMMO just send 12V there? Can this been done around the IMMO with a bypass? And finally: the schematics in above link show another connection from IMMO pin 4 to ECM pin B36. Is the there shown mode symbol a handshake between key an ECM?

Thanks for bearing with me, really appreciate!

jmartin919 · Post by **jmartin919** » 12 Jul 2024, 16:06

That wiring diagram is different from what I have. The link you sent is for a '99. The signal from the IMMO is a wave form I believe, so you would need an oscilloscope or similar.

MotorTheresa · Post by **MotorTheresa** » 13 Jul 2024, 10:27

@jmartin919 wow, this is excellent! Thanks!
Finally we get to have a look inside the dreaded box. Need to compare my test notes / measurements of pins 1-10 of the IMMO connector with ignition off, ignition on, and start to make more sense and conclude if the IMMO3 itself is shot or not.

Ultimately I need to decide next steps: either
ECM+IMMO3+key from a donor
Or
IMMO3+key from a donor
Or
Finding a way (or supplier) to make the ECM no longer looking for the IMMO input.

Thanks!

(Would you be able to put me in a direction to get more schematics for the 1998 10V? All I found so far is 20V...)

jmartin919 · Post by **jmartin919** » 13 Jul 2024, 12:47

What I have does not distinguish between 10V and 20V. The Service Manual has an incomplete components list so I attached separate docs for that but don't know what year they're applicable to. I have a 2000 S70 so I would guess they're for that.