Ben,

We had a similar problem last month.

I checked the resistance of the accelerator position sensor and the two sensors seemed correct and I also looked at the voltages which appeared ok. If I remember correctly one sensor tracks 0 to 5V and the other 0 to 2.5V (i.e. half the other).

We tried a known good sensor and the problem was still there. What I then noticed is on the live data the second sensor circuit was showing less than half the voltage. We pulled the ECU, checked and cleaned the terminals and refitted and problem went away.

There must have been a high resistance at the ECU connector or a possible break in the signal wire on second sensor circuit (which may come back again).

The ECU checks that the second sensor circuit is half the main sensor value....if it deviates from this it sets the ratio DTC.

HTH

Sean