I have been searching for close to a month and found nothing that works. I can't pull codes or use dsm link on my 93 Laser. I have continuity between pin 1 on obd and 1 on ecu, and pin 10 on obd and 2 on ecu. Pin 12 is grounded well. All fuses are good. This has happened on 2 different ecus so even though it's possible I don't think it is the ecu. I am using a test light and the dsm cable to check for it working, both come out negative. Open to any and all ideas. Thanks

Refer to: 1G basic ECU MPI circuit function

Does the CEL come on for 5 seconds when the ignition is turned to "On"? If turbo, does the boost gauge go to zero at the same time? These should happen simultaneously with the diagnostic port "heartbeat" at ECU pin 1. Check this at the ECU itself. No pulsing or, in other words, constant voltage at ECU pin 1 indicates a malfunctioning ECU.

Same problem 1990 TSI, no power at obd port, also cylinder#2 and #3 weak or no spark. Changed plugs , wires , coil, and checked connections and ground at intake manifold. Power transistor tested good according to Haynes manual instructions.

I have ECM link but have not installed yet. If I install it I still can't use for diag since no power at obd port?

Can the weak/no spark and obd no power be related? I need help badly. Been trying to figure it out for 3 weeks. Thanks

Vincent Pandolph said:

Same problem 1990 TSI, no power at obd port.

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No surprise there, the 1G OBD 1 connector doesn't have a power source on it unlike a OBD 2 connector.

1 - ECU Data
5 - Cruise Control Data
6 - ATX TCU Data
10 - ECU Diag Mode
11 - VSS
12 - Ground

Ok so thanks for clearing that up. I don't want to just keep throwing money at it. I have a the original ECU getting rebuilt and I have an eprom socket in the car now. If I hook up ECM link can I use that to test the sensors? I'm looking at old posts and see some people resolved issues by replacing the CAS. I already ordered a new ptu. When that comes in and the fresh ECU I will update on progress. Any way to test the CAS? Do they get dirty?

All the tests are in the FSM, do you have one yet? A Haynes manual isn't the same.
I'm sure there are a few threads here for just about everything but you might have to use a google search rather than the local site search.

Fsm? I've been reading threads for weeks now. Using info for tests and such. I'm checking for continuity for data pin from ECU to obd port tomorrow and I will test the ground on obd port. If those are good I will put ECM link Chip in and see if I can get any useful info from that. Maybe my caps went bad?

Factory Service Manual

One more question, will ECM link connect to an eprom ECU with stock chip?

Vincent Pandolph said:

One more question, will ECM link connect to an eprom ECU with stock chip?

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Not supported. It would be nice but I don't think it works.