The Driver Wish map is probably the most misunderstood map in a diesel ECU file. I’ve seen calibrators raise every value in it by 20% and then wonder why the car didn’t respond.
Let me explain what this map actually does.
What Driver Wish is
It’s a conversion table. Input: pedal position and engine RPM. Output: a torque request in Nm.
The map translates driver foot pressure into engine torque demand. It does not control fuel. It does not control boost. It is a request — not a command.
Why raising it doesn’t always give more power
Because the request then goes through a stack of limiters:
- Torque monitoring (from the transmission ECU)
- Smoke limiter (tied to air mass)
- Thermal limiter
- Drivetrain limiter (max torque the gearbox is rated for)
If any of these limiters are set below the Driver Wish value, they clip the request before it reaches the fuel calculation.
When raising Driver Wish actually makes sense
If you’ve verified the limiters have headroom, and the car is not producing the torque it theoretically could — then adjusting Driver Wish reshapes the pedal response.
What to check before touching it
- What does the smoke limiter allow at that RPM?
- Does air mass support the fuel quantity needed?
- Is there a coordinator torque cap from another ECU?
In Diesel Fundamental, we trace the full torque path in Chapter 2 — Driver Wish through every limiter — with annotated ECU files.