DTC 19

Fig. 15 Fuel Pump & Injector Wiring Circuit:

With ignition on, ECM energizes fuel pump relay for two seconds and feeds 12 volts to fuel pump circuit. Unless distributor reference pulses are received within this time, ECM will de-energize relay so that fuel pump will not continue to run with ignition on. Code 19 indicates that fuel pump relay circuit continues to have 12 volts after two second prime. Possible causes of this condition are:
a. Faulty fuel pump relay.
b. Faulty oil pressure switch.
c. Defective wiring harness or electrical connectors.
d. ECM not processing fuel pump signal or not turning relay off.
To diagnose a Code 19, proceed as follows:
1. If unwanted source of voltage can be eliminated, self-diagnostics can be used to detect this by displaying parameter .1.0. When voltage is removed from circuit, ``battery voltage'' reading will drop to 0 volts.
2. Eliminate branches of fuel pump circuit first by removing oil pressure switch connector. If ``battery voltage'' reading is now 0, oil pressure switch must be replaced because it is closing switch without receiving oil pressure.
3. If ``battery voltage'' reading is still greater than 0 volts, another portion of fuel pump circuit can be eliminated by removing fuel pump relay.
4. If ``battery voltage'' reading is still greater than 0 volts, inspect circuits 120 and 120E for a short to voltage.
5. If voltage on circuit 120 is greater than 0 volts when ECM is disconnected, the circuit is shorted to voltage. If voltage reading is 0, fault must be in ECM connector or in ECM.
6. If ``battery voltage'' reading is now 0 after removing fuel pump relay, probe relay socket cavity 5 with a test lamp to ground. With ignition on, test lamp should light for two seconds, then go out. If light goes out, replace relay.
7. If light stays on, either ECM or wiring harness is shorted to voltage. If there is voltage on circuit 465 with ECM disconnected, circuit is shorted to voltage. If voltage is 0, check for faulty ECM or ECM connector.