DME 7.8 DME 7.8 0 · 0-62P0420

DME 7.8 DME 7.8 0 0-62P0420 40 TWC conversion, bank 1 - above limit Diagnosis conditions • TWC temperature 420 - 600 °C • 85 seconds within rpm/load range (cumulative) • EVAP canister burden < 8 • Speed 1280 - 2440 rpm • 20 - 40 % engine load (relative air charge) • Oxygen sensing ahead of TWC is active • Oxygen sensing after TWC ready for operation • Engine starting temperature > - 20 °C • No faults in memory Possible fault cause ♦Oxygen sensor ahead of and after TWC exchanged ♦Valve lift fault ♦Aged oxygen sensor after TWC ♦TWC faulty Affected terminals - Diagnosis/troubleshooting Note! If an ageing oxygen sensor is recorded in conjunction with a fault in the TWC, a check must be performed with a new oxygen sensor to see whether a TWC fault is still indicated. Work instruction Display OK If not OK 1 Check whether the oxy- gen sensors ahead of and after the TWC have been exchanged 2673 P0420 0-62 page 1 Printed in Germany, 2000 p0420