Cumminz

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.This fault is set active if the ECM does not receive the Heartbeat message from the adaptive cruise control unit on the SAE J1939 data link. If Adaptive Cruise Recovery is enabled, the driver can toggle the cruise enable switch from the OFF position to the ON position two times to get regular cruise control to operate and Fault Code 784 will go inactive. At the next key...

Circuit DescriptionThe ECM has internal diagnostics that continuously run and check the internal memory. Component LocationThe ECM mounting location varies depending on engine model and can be mounted either on or off engine. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position. Conditions for Setting the Fault CodesThis fault code is triggered when the internal ECM diagnostics detect a read or write error internal to the module. Action Taken When the Fault Code is ActiveThe ECM illuminates the red STOP ENGINE light and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs...

Circuit DescriptionThe engine control module (ECM) receives constant voltage from the batteries through the unswitched battery wires that are connected directly to the positive (+) battery post. The ECM receives switched battery input through the vehicle keyswitch wire when the vehicle keyswitch is turned on. Component LocationThe ECM is connected to the battery by the OEM power harness through the ECM battery supply stub. This provides a constant power supply for the ECM. The location of the battery will vary with the original equipment manufacturer (OEM). Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the...

Engine Magnetic Speed/Position Lost Both of Two Signals – Data Erratic, Intermittent, or Incorrect Circuit DescriptionThe crankshaft position and camshaft position sensors are Hall effect type sensors. The engine control module (ECM) provides a 5 volt supply to the position sensor and a return circuit. As the teeth on the crankshaft speed ring or the dimples in the back of the camshaft gear move past the position sensor, a signal is generated on the position sensor signal circuit. The ECM interprets this signal and converts it to an engine speed. A missing tooth on the crankshaft gear is used by...

Circuit DescriptionThe engine control module (ECM) provides a 5 volt supply to the intake manifold pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The intake manifold pressure sensor provides a signal to the ECM on the intake manifold pressure sensor signal circuit. This sensor signal voltage changes based on the pressure in the intake manifold. The ECM will detect a low signal voltage at operating conditions such as during an idle or a deceleration. The ECM will detect a high signal voltage during high engine load operating conditions. Component LocationThe...