Operation Section Table 2. Diagnostic Fault Codes (Flash Codes) cont’d. (*) Fault actions shown are default values specified by the OEM. 69 DFC PROBABLE FAULT FAULT ACTION * CORRECTIVE ACTION FIRST CHECK 381 (38) IATRangeHigh Intake Air Temperature Sensor Input is High normally set if the IAT temperature sensor wire has been disconnected or the circuit has opened to the SECM. TurnOnMil Check TMAP connector and IAT signal wiring for a shorted circuit TMAP Pin 2 to SECM Pin B12 (signal) TMAP Pin 1 to SECM Pin B1 (sensor GND) To check the IAT sensor of the TMAP disconnect the TMAP connector and measure the IAT resistance Resistance is approx 2400 ohms at room temperature.
391 IAT IR Fault _ _ Intake Air Temperature not changing as expected None Check connections to TMAP sensor. Check that TMAP sensor is properly mounted to manifold. 421 EST1 Open _ EST1 output open, possibly open EST1 signal or defective spark module TurnOnMil Check coil driver wiring and connector for open circuit SECM Pin A9 (EST1) to OEM ignition system. See application note. Verify GND on ignition module Pin A (of both connectors) Verify +12 Vdc on ignition module Pin B (of both connectors) Refer to application manual for specific engine details.
422 EST2 Open _ EST2 output open, possibly open EST2 signal or defective spark module TurnOnMil Check coil driver wiring and connector for open circuit SECM Pin A10 (EST2) to OEM ignition system. See application note. Verify GND on ignition module Pin A (of both connectors) Verify +12 Vdc on ignition module Pin B (of both connectors) Refer to application manual for specific engine details. 423 EST3 Open _ EST3 output open, possibly open EST3 signal or defective spark module TurnOnMil Check coil driver wiring and connector for open circuit SECM Pin A3 (EST3) to OEM ignition system. See application note.
Verify GND on ignition module Pin A (of both connectors) Verify +12 Vdc on ignition module Pin B (of both connectors) Refer to application manual for specific engine details.