DTC 64

This diagnostic procedure does not detect troubles in switches and injectors. If this occurs, the control unit may analyze the case and give air flow sensor trouble codes or abnormal oxygen sensor output code.

Fig. 74 Fuel injector power transistor circuit identification.:

Fig. 75 Fuel injector power transistor resistance value chart.:

1. Check resistance of power transistor circuit as shown in Fig. 74, then compare with specifications in chart, Fig. 75. On 1988 Impulse, terminal Nos. 31 and 32 have been changed to terminal Nos. 6 and 7 and on 1988 Trooper II, terminals No. 31 and 32 have been changed to terminals Nos. 1 and 2.
2. If measured resistance is not as specified, repair or replace defective parts.