DTC Advanced Diagnostics: P16E4

DTC P16E4:ACG High-temperature

General Description

Driven by the engine, the alternator generates electricity according to the commands from the powertrain control module (PCM). The local interconnect network (LIN) line is connected to the alternator and transmits/receives information to/from the PCM. The PCM sets a target generating voltage in the range of 12.5 V to 14.5 V and commands the alternator via the LIN line. The alternator output signal (duty signal) is sent to the PCM, and is varied according the 12 volt battery’s state of charge, the electrical load, and the engine speed. The voltage regulator in the alternator runs a self-diagnostic function by PCM command, the results are transmitted via the LIN line. If the self-diagnosed results are judged that the alternator temperature is too high, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status

Execution	Continuous
Sequence	None
Duration	60 seconds or more
DTC Type	One drive cycle, MIL off
OBD Status	PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Enable Conditions

Condition
Vehicle	ON mode
No active DTCs set (prevents monitor from running)	P16E2

Malfunction Threshold

The alternator internal temperature is 374 °F (190 °C) or more, for at least 60 seconds.

Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

	Ambient temperature extreme increase
	Alternator internal failure

Diagnosis Details

Conditions for setting the DTC

When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory. The MIL does not come on.

Conditions for clearing the DTC

The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.