Converted Harness

1. Inspect Factory Porsche Round Connectors

While the engine is out and you have space, thoroughly check both chassis-side factory round connectors. We frequently see unseated or loose pins in the Porsche harness.

1. • Verify every pin is fully seated and will not back out when pushed.

2. Routing a Converted Harness (ECU on Manifold)

If you’re using our converted harness with the ECU mounted on the manifold:

2. • Route all connections before installing the engine.

   • Zip-tie critical areas, especially the sharp bend over the valve cover.

   • Use the supplied cushion clamp to support the harness on the valve cover.

   • Plug the ECU into the harness and place it in the supplied manifold bracket.

     • Confirm the ECU is immobilizer-defeated (ME7.1.1 BEL), as accessing it after installation is difficult.

3. Re-pin the Audi Connectors to Porsche Style

   • Refer to the image carousel below and your specific engine/chassis Re-pin Diagram

4. Automatic Engine Harness Conversion: Clutch to ECU

Automatic 2.7T harnesses do not include the CC clutch signal needed for proper Renn27 tuning behavior. You must add the clutch signal from the Porsche body connector to ECU pin 39.

Repurpose wire method

1. Move a Wire at the ECU Connector

Move either of the following wires to ECU pin 39:

1. • Pin 40 (black/yellow) or Pin 41 (black/grey)

(Choose whichever color you prefer to keep consistent.)

2. Match the Color at the Porsche Lock Ring Connector

From the Audi red connector:

2. • Pin 2 (black/yellow) or Pin 3 (black/grey)

Populate this wire into:

2. • Porsche black lock ring connector, Pin 14 (1999) or Pin 6 (2000+)

5. ME7.1.1 (BEL) Unswitched ECU Power (UPDATED)

Bypass the O₂ relay in the rear seat area.

5. • Locate the factory O₂ relay under the rear seat.

   • Remove the relay.

   • Install the provided O₂ jumper into the relay socket.

   • This jumper supplies the ECU with the required unswitched 12V feed.

   • This replaces the need to modify any wiring on the BEL harness.

   • Memory retention will now function correctly.

6. Recommended ME7.1 (APB) Updates

We strongly recommend updating your APB engine to modern coil packs with ICM delete.

6. • Suggested kit: ECS Tuning Coil Conversion

7. Sensor Extensions Required - Reference: Harness Overview

Some Audi connectors become unreachable once the engine is in the car. Extend these before installation:

• MAP sensor → lengthen approx. 12”

• N75 valve → lengthen approx. 18”; mount on front passenger side of intake manifold as shown

• MAF sensor → lengthen approx. 32”

8. Connectors Typically Not Used With Renn27 Tuning - Reference: Harness Overview

If you are using Renn27 tuning, the following factory connectors are generally unused:

EGT Sensors

8. • G235 (Sensor 1): blue/brown, green/yellow, brown wires

   • G236 (Sensor 2): blue/red, green/yellow, brown wires

Secondary Air Injection (SAI) System

All SAI equipment is unused. Manual ME7.1 (APB) harnesses do not have SAI.

8. • SAI fuse (40A, red/black & red wires)

   • SAI motor (brown & red/yellow wires)

   • SAI relay (red/yellow, red/black, blue/gray, green/yellow wires)

   • SAI solenoid (green/yellow & yellow/green wires)

Rear O₂ Sensors

8. • Brown rear O₂ plug (yellow/white, violet, red, black wires) is not used

   • Green rear O₂ plug is used for optional wideband input

     • AEM 5V signal → connect to pin 69 OR the blue wire on the green O₂ plug

N80 Valve

8. • Can be deleted (violet/white & green/yellow wires)

Automatic Harness Only

8. • G294 Brake Booster Pressure Sensor (brown/grey, green/black, grey/yellow wires) 

9. Power & Ground Requirements

   • Use a large 4 AWG ground strap from engine to chassis. (Either Porsche chassis ground or Audi engine ground locations are acceptable.)

   • The Porsche primary power cable will reach the Audi starter/alternator area if you reposition the transmission-tunnel junction point. Then add a short 4 AWG cable to tie the alternator and starter together (factory 2.7T cable works if present).

   • On the chassis side, locate the factory Porsche SAI connector—this becomes the power and ground feed for the air-to-water intercooler pump controlled by the Renn27 DME.

10. Final Installation Steps

    • Move the OBD-port pin according to your Renn27 re-pin diagram.

    • Install the engine.

    • Plug the converted round connectors into the Porsche connector station.

Jumper Harness (Legacy)

1. Pull the entirety of the remaining circular twist lock connectors and Porsche engine wiring harness back into the rear shelf area, the Renn27 connection will be made inside the vehicle, in the rear shelf area. Remove all of the rear shelf carpeting and unbolt the aluminum covers to access the Porsche DME. This is where the Renn27 junction box will reside, in the original location of the Porsche DME. 

2. The Audi wiring harness will now need to get pulled through the same access hole to the rear shelf area, as the connections from the Audi harness to the Renn27 jumper harness will reside here. You will also place the Audi ECU in this area. You can apply double sided tape to the bottom of the ECU to keep it secure to the rear shelf surface if desired. 

3. You will want to lengthen some of the Audi electrical connectors from their original location, as they will be inaccessible once the engine is in the vehicle. 

   • Lengthen the MAP sensor about 12"

   • Lengthen the N75 about 18", and mount it on the front passenger side of the intake manifold as shown

   • Lengthen the MAF sensor about 32"

   • **********Lengthen the Porsche harness about 18" as this is still part of the Porsche engine harness that will be retained. 

4. Here are some connectors that will likely NOT be used if you are using Renn27 for tuning 

   • EGT sensors

   • All secondary air equipment including the fuse and relay near the ECU. Note: Manual APB harness dose not have SAI.

   • Brown rear o2 sensor plug. Green WILL be used for wideband tuning if desired for maximum HP tuning.

   • N249 valve does not have to be used if you are using Renn27 tuning.

5. Be sure to use a large ground (at lease 4 gauge) from engine chassis sourced from either the Audi engine or Porsche chassis.

6. The Porsche primary power cable will reach the Audi starter / alternator area if you reposition the bolted connection in the transmission tunnel. You will then need to make a small 4 gauge wire to connect the alternator and starter.

7. Move pin 9 violet/green to pin 7 orange/black on the OBD port. Leave orange/black disconnected.