LT‑Swap Wiring Guide for BMW E9x/E8x Chassis (GM E92 ECU)
UNDER CONSTRUCTION
This guide shows how to wire a GM Gen‑V LT engine with an E92 ECU into a BMW E9x/E8x chassis. It reuses all the BMW chassis wiring specifics from the original Lse9x Holley LS swap wiring guide but updates the ECU‑side connections for the GM E92. The BMW connectors and harness remain largely the same; the differences lie in the drive‑by‑wire pinouts and fan/compressor control signals. Use this as a stand‑alone reference for Gen‑V swaps.
The wiring that is left on the chassis side after the engine harness is removed will be slightly different based on if that car was automatic or manual, and the year of the car. The basic breakdowns are found below.
Key‑On Ignition Power
- Recommended source: Install a fuse tap at the cigarette‑lighter fuse (fuse 8 or 30 or other, depending on year). This provides 12V Ignition power when the car is in accessory power mode and cranking.
- Alternative source: Connector X6011 pin 6 (green/white). This wire is a terminal power wire and will turn on during self checks and other events and can cause battery drain issues, not recommended for use
- Run this wire to the ignition input of your Gen‑V swap harness. Typically LT standalone swap harnesses will have a built in fuse/relay for ignition power.
Constant 12V Supply
- Use the main jump‑start stud on the passenger strut tower. The large stud is unfused; the small stud is fused by a fusible link above the battery.
- If the small stud has no power, check the fusible link. Do not use the small stud for high‑current loads such as the starter or alternator.
- Run a proper cable from the large stud to the constant power lead of your harness if required
- Most LT swap harnesses have a main power ring terminal that will be located at the starter but may vary based on the harness used.
Ground
- Ground can be sourced from any major chassis ground stud. Ensure the engine block and alternator have solid grounds
-
PRO TIP COMMON ISSUE: the LSe9x alternator bracket is powder‑coated and does not conduct ground well for proper charge. LT brackets retaining factory aluminum alternator will not have a ground issue.
Cooling Fan Control (Updated for Gen‑V)
The BMW electric fan’s power and ground remain stock. Its speed is controlled by a single PWM wire (X60001 pin 8). In LS swaps, Holley output wires drive this PWM signal. For the Gen‑V E92 ECU:
- E92 pin X1‑59 is the high‑speed cooling‑fan relay control. It provides a low‑side PWM output. This is typically broken on on standalone harnesses as fan control. Tune will need to be configured for PWM fan control.
Drive‑By‑Wire Accelerator Pedal
Six wires from BMW connector X60001 must be routed the pedal connection.
The PCM pinout below is shown for diagnosis purpose.
| BMW pin | BMW wire color | E92 pin & function | Notes |
|---|---|---|---|
| 7 | White/yellow | X1‑34 – Pedal position signal 2 | sensor 2 |
| 20 | White | X1‑15 – Pedal position signal 1 | sensor 1 |
| 11 | Yellow | X1‑14 or X1‑33 – 5 V supply | 5v supply to pedal |
| 24 | Yellow/green | X1‑33 or X1‑14 – 5 V supply | 5v supply to pedal |
| 10 | Brown/yellow | X1‑30 – Pedal low‑reference | Sensor ground |
| 23 | Brown | X1‑53 – Pedal low‑reference 2 | Sensor ground |
Your harness should include a 6 pin pedal DBW connector labelled A–F, wire the BMW signals to pins A–F accordingly. Car/Corvette and truck harnesses share the same plug but swap pins A and C; for truck harnesses swap the 5‑V and ground leads. Truck Harnesses will have 2 5v wires in the center positions C and D
https://www.youtube.com/watch?v=mq3EWb7FGxY
| BMW pin | BMW wire color | E92 Pedal Connector | Notes |
|---|---|---|---|
| 7 | White/yellow | b | sensor 2 |
| 20 | White | e | sensor 1 |
| 11 | Yellow | c | 5v supply to pedal |
| 24 | Yellow/green | d | 5v supply to pedal |
| 10 | Brown/yellow | a | Sensor ground |
| 23 | Brown | f | Sensor ground |
| BMW pin | BMW wire color | E92 Pedal Connector | Notes |
|---|---|---|---|
| 7 | White/yellow | b | sensor 2 |
| 20 | White | e | sensor 1 |
| 11 | Yellow | a | 5v supply to pedal |
| 24 | Yellow/green | d | 5v supply to pedal |
| 10 | Brown/yellow | c | Sensor ground |
| 23 | Brown | f | Sensor ground |
BMW Starter CAS to Brake‑Switch Mods
Based on how the car will function with the brake or clutch pedal one of the following will need to be followed. Car Access System CAS require a 12v (brake‑light or clutch signal) to reach the CA) so the Start/Stop button will send the signal to the starter solenoid crank the engine. Without this signal the car will simply shut off the ignition rather than try to start the car.
PRO TIP COMMON ISSUE: If you car is trying to crank the starter without the brake depressed, first check that your brake lights are not stuck on. Very commonly during swaps the switch becomes out of adjustment. Push the brake switch against the brake pedal so it touches, it is a magnetic sensor.
Automatic Cars Going Automatic/Manual Starting With Brake Pedal
- Connect blue/red **pin 4 (brake‑light signal)** on X60001 to the blue/black wire on one of the following: On pre‑03/2007 cars this wire is on an 8‑pin X6031 connector; post‑03/2007 cars use a 12‑pin version. Verify the wire with a wiring diagram.
- When the brake pedal is pressed, this jumper sends 12 V to CAS pin 41, enabling the Start/Stop button.
Pre 03/07 (n54/n52) - x6031
Post 03/07 (n54/n52) - x6031
Manual Transmission Cars Going Automatic
If converting a manual E9x/E8x to automatic:
- Tie the blue‑brown wire (pin 18) to the blue‑red wire (pin 4) on the X60001 connector. This bridges the clutch switch to the brake signal.
- At the clutch switch, join the blue‑brown wire to the blue‑black wire. This ensures pressing the clutch pedal (now unused) sends a brake signal for starting.
Manual Transmission Staying Manual
- Will retain factory clutch switch wiring and no mods needed
Starter Solenoid
- Run a 10‑gauge wire from **X6011 pin 3** (pre‑03/2007) or **pin 1** (post‑03/2007) to the starter solenoid.
- Starter diagnostics in the GM ECU will need to be disabled in the tune
Pre03/07 (n54/n52) - x6011
Post 03/07 (n54/n52) - x6011
BMW Automatic Transmission PT‑CAN Termination
- Automatic cars need termination on the PT‑CAN network. On connector **X6021**, connect pin 1 to pin 3 and pin 2 to pin 4 (the two matching pair of red blue PT can wires). This prevents PT CAN‑bus errors (e.g., wipers that stay on).
LSe90 CAN Box Connections
- The CAN box’s blue/red twisted pair goes to **X60001 pin 1 (PT‑CAN low)** and **pin 14 (PT‑CAN high)**.
- On the ECU side, connect the CAN box to **E92 pin X1‑40 (CAN low)** and **X1‑39 (CAN high)**. These wires are also available at the obd2 connection, The CAN box mimics the GM BCM and forwards signals (like A/C requests and alternator control) to the ECU.
A/C Compressor and Pressure Sensor (Gen‑V Specific)
- A/C compressor clutch: Use **E92 pin X1‑32**, which is the A/C compressor clutch relay control. This will be a ground signal from the PCM to trigger a relay, wire it to a relay that powers the compressor clutch.
-
A/C pressure sensor: Adapt a GM pressure transducer to the BMW A/C line. Connect its three wires to E92 pins:
- X1‑6 – A/C refrigerant pressure sensor signal;
- X1‑21 – 5 V reference;
- X1‑22 – Low‑reference (ground).
- The LSE9x LT CAN box handles A/C requests from the BMW climate control sending it to the GM ECU via Can bus, allowing the ECU to energize the compressor clutch when appropriate based on ac pressure
- Fan speed is also controlled by A/C pressure in the GM ECU.
BWM EKP delete and fuel pump wiring
The BMW E9X chassis uses an EKP (Electronic Fuel Pump Controller) to control pump speed and operation. This system is designed to work with the factory BMW ECU over CAN and will not function correctly with a GM ECU.
EKP is located behind the right hand side side panel of the rear seat. This module will be unplugged and replaced with a QUALITY 30/40 amp standard automotive type relay for the fuel pump.
IT IS VERY IMPORTANT THESE CONNECTIONS ARE DONE WELL. High current fuel pump 
The EKP has 2 connectors, One smaller connector with two larger gauge wires leading to the fuel pump, brown (ground) red 12v.
The larger connector you can source 12v from the red wire (fused from the factory fuel pump fuse) and ground, brown wire
above is a ekp wiring diagram for reference from a 2007 328i
Wire the Relay- This can be done many ways but the following is typical to switch the 12v signal to the pump with the relay.
-
Pin 85 → Ground from EKP large connector brown, Or a ring terminal to the ground point where the ekp mounts
-
Pin 86 → GM 12v fuel pump trigger wire (12 V signal when pump should run)
-
Pin 30 → 12 V fused power feed from (large EKP connector red wire)
-
Pin 87 → Positive wire going to the fuel pump (small ekp connector red wire)
Brown wire from the small ekp connector( fuel pump ground wire) should be ground from EKP large connector brown (same as pin 85), Or a ring terminal to the ground point where the EKP mounts
Summary of Key GM E92 ECU Pins
| Pin | Function | Notes |
|---|---|---|
| X1‑14 / X1‑33 | 5 V pedal supply | BMW pins 11 & 24. |
| X1‑15 / X1‑34 | Pedal position signals 1 & 2 | BMW pins 20 & 7. |
| X1‑30 / X1‑53 | Pedal low‑reference (ground) | BMW pins 10 & 23. |
| X1‑51 | Run/Crank ignition input | Connect to key‑on wire. |
| X1‑52, X1‑70, X1‑73 | Constant battery positive | Main power feed. |
| X1‑59 | Cooling‑fan relay control | Drives fan controller. |
| X1‑63 | Starter‑enable relay | Optional start control. |
| X1‑32 | A/C compressor clutch relay | Controls A/C clutch. |
| X1‑6 / X1‑21 / X1‑22 | A/C pressure sensor signal / 5 V / ground | Connect GM pressure transducer. |
| X1‑39 / X1‑40 | CAN high / CAN low | Connect to CAN box. |
X60001
Pin assignments at plug connector X60001
| Pin | Type | Description /Signal type | Connection /Measuring notes |
| 1 | E/A | Signal PT-CAN low | Powertrain CAN-bus |
| 2 | E | Start signal | Car access system |
| 3 | E/A | BSD signal | Battery sensor |
| 4 | E | Brake light signal | Brake light switch |
| 5 | A | Signal, exhaust flap | Exhaust flap |
| 6 | E | Signal Temperature sensor at radiator outlet | Temperature sensor at radiator outlet |
| 7 | E | Signal Accelerator pedal module | Accelerator pedal module |
| 8 | A | Signal Electric fan | Electric fan |
| 9 | A | Activation | Radiator shutter drive unit |
| 10 | M | Ground Accelerator pedal module | Accelerator pedal module |
| 11 | A | Supply Accelerator pedal module | Accelerator pedal module |
| 13 | A | Activation Secondary air pump relay | Secondary air pump relay |
| 14 | E/A | Signal PT-CAN high | Powertrain CAN-bus |
| 15 | E | Signal, electronic vehicle immobilizer | Car access system |
| 16 | E | Brake light test signal | Brake light switch |
| 17 | E | Signal, rear right wheel speed | Connector X10186 (rear right wheel speed) |
| 18 | E | Signal, clutch switch | Clutch switch module |
| 19 | E | Signal Temperature sensor at radiator outlet | Temperature sensor at radiator outlet |
| 20 | E | Signal Accelerator pedal module | Accelerator pedal module |
| 21 | E/A | TD signal | Connector TD signal |
| 22 | E | Supply, terminal 15 | Car access system |
| 23 | M | Ground Accelerator pedal module | Accelerator pedal module |
| 24 | A | Supply Accelerator pedal module | Accelerator pedal module |
| 25 | E | USA Signal Secondary air - hot-film air-mass meter | Secondary air - hot-film air-mass meter |
| 26 | A | Signal, E-box fan | E-box fan |
