T7 pbus

No matter which interface you are/will be using to connect to your Trionic 7 ECU/ECM, you will need to tap into the Powertrain Bus somewhere. The different ways to do this has previously been spread out all over the forum (and the internet). Let’s get it all into this thread, and (in time) the first post.

Note: 9-5 Model years 2008-2010 should have the P-Bus connected to OBD socket already, check if Pin 6 & 14 are populated in your car.

The P-BUS is a Highspeed CAN bus, which lets the different powertrain computers in the car talk to each other.

Wiring info:

PBUS consists of two wires; Green (HI, +) and White (LO, -) and can be found in several locations in the cars, depending on car model, model year, and equipment level. These locations are listed further down in this post. (NOTE: I-BUS wiring is also white & green, so make sure you know what you tap into!)

You splice/crimp/solder your own wires onto the existing ones. I prefer to use parallel soldering as seen below (don’t forget to insulate!)

Then connect them to your PC via one of the supported interfaces. Most people choose to route the wires to the OBD socket for easy access.

Remember that the PBUS/CAN wires MUST be twisted to prevent data loss and/or poor connection. This is easily done with a bench vice and a drill, like this (aim for 10-15mm or so between twists):

You can use regular twisted network cables if you want. Cat 5/6/7 FTP/STP would probably be best, but UTP should work fine too.

Some/most people choose to connect the P-BUS to their OBD socket for easy connection to OBDLink and other interfaces, some choose to make a completely custom solution with their own socket etc. It’s up to you.

If you decide to connect the wires to the OBD socket, you will need two pins (Saab part number 4466801) and a suitable crimp tool for uninsulated terminals, for example Elpress DRB0115. Crimp them like this:

P-BUS Locations:

9-5 1998-2010:

1. SAS (Steering Angle Sensor), below steering column. This is the easiest one to use, but it is ONLY available on cars with ESP.

• 02-10: Pin 4 (White), Pin 3 (Green)

2. TCM (Transmission control module), behind glove compartment, next to the T7 ECM. ONLY on Automatic cars. Pictured is a 1999.

• 98-98: Pin 22 (White), Pin 1 (Green)
• 99-01: Pin 10 (White), Pin 9 (Green)
• 02-10: Pin 26 (White), Pin 25 (Green)

3a. Trionic 7 wiring loom. All cars. ECM is located behind glove box, but wiring loom is only accessible from the engine bay/wiper area. If you tap in to PBUS here, the wires can be dropped down into the cabin in the same hole the T7 sits mounted in. Remember to leave some slack up there though.

• Pin 19 (White), Pin 66 (Green)

3b. T7 PBUS wiring can also be found on the upper firewall, engine side.

• 98-98: Connector H70-1, Pin 29 (White), Pin 28 (Green)
• 99-04: Connector H42-5, Pin 29 (White), Pin 30 (Green)
• 05-05: Connector H24-1, Pin 2 (White), Pin 1 (Green)
• 06-10: Connector H24-2, Pin 8 (White), Pin 9 (Green)

4a. MIU (Main Instrument Unit) wiring loom. All cars. It might be possible to reach these wires from underneath the dash somewhere, since they come from the engine bay.

• 98-01: Pin 11 (White), Pin 4 (Green)
• 02-05: Pin 9 (White), Pin 17 (Green)
• 06-10: Pin 20 (White), Pin 21 (Green)
• 06-10: Pin 4 (White), Pin 5 (Green) (These go to the OBD socket)

4b. 06-10: Connector H33-1, Pin 15 (White), Pin 16 (Green). This connector should be somewhere in/near the relay central under dash.

5a. ABS/ESP/TCS unit. Behind the battery in engine bay. Probably only cars with either TCS or ESP. Pictured is a 2003 ESP.

• 00-04: Pin 29 (White), Pin 30 (Green)
• 05-10: Pin 14 (White), Pin 35 (Green)

5b. Wires from ABS/TCS/ESP could also be possible to find underneath the dash somewhere. The connector to use there is H43-1, Pin 9 (White), Pin 10 (Green). Left side of the car, at least on LHD cars). The H43-1 connector at drivers side (left side sen from the rear) footwell by the A-pillar there's also P-bus on TCS cars. So for early cars without ESP, but with TCS, this a possible spotm but it's rather tight and very little wire to work with

9-3 1999-2003:

Unfortunately, I have no photos for these as my only 9-3 is kinda blocked in by a gazillion other cars so I can’t really get to it. Someone?

1. T7 ECM Wiring loom, Lower A-pillar (right side). Pin 19 (White), Pin 66 (Green)

2. Connector H33-5, Pin 32 (White), Pin 16 (Green)

• LHD: Grey connector on firewall behind glove compartment
• RHD: Grey connector below T7 ECM

3. TCM Unit: Right side of firewall, in cabin. Only automatic cars.

• 00-03: Pin 10 (White), Pin 9 (Green)

4. MIU (Main Instrument Unit):

• 99-01, Pin 11 (White), Pin 4 (Green)
• 02-03: Pin 9 (White), Pin 17 (Green)

5a. ABS/TCS unit (probably only on cars with TCS?)

• 01-03: Pin 29 (White), Pin 30 (Green)

5b. Connector H6-12, Behind right strut tower (probably only on cars with TCS?)

• 01-03: Pin 6 (White), Pin 5 (Green)