What this code means
P16E2 may mean the PCM is not receiving expected alternator information over the LIN communication circuit.
What the vehicle may do
- The vehicle may show a charging-system warning.
- Auto idle stop may be affected on equipped vehicles.
- The vehicle can sometimes appear to drive normally while the code is stored.
Possible fault areas
- Possible loose alternator +B terminal concern.
- Possible LIN communication circuit open or short.
- Possible shorted component connected to the shared LIN circuit.
- Possible alternator-related concern.
- Possible PCM concern after other checks are normal.
Diagnostic path
Opening and code logic
On this CR-V, P16E2 is about the PCM not getting the alternator signal over the LIN communication line. In plain terms, the charging system may still have parts powered up, but the PCM may not be seeing the alternator talk back the way it expects. The driver may see charging-system warnings, auto idle stop may be affected, or the vehicle may act fairly normal while the code is stored. The broad fault areas are possible alternator terminal issues, LIN circuit problems, a shorted component on that shared line, alternator-related faults, or, after the other checks pass, a possible PCM issue. Start with the basic system checks, then look closely at the alternator +B terminal. If that +B terminal is loose, P16E2 will be stored, so do not skip that simple check before getting deeper into the network testing.
Confirmation and branch point
Next, run the confirmation step. Turn the vehicle to the ON mode and wait 10 seconds. At that point, look at whether the related alternator communication code is also present. Do not read that as a repair by itself; use it only to decide which side of the diagnostic path you are on. If the branch return is not clear while you are working through the chart, pause, recheck the earlier diagnostic path, and avoid guessing.
LIN circuit inspection setup
For the LIN battery-sensor circuit inspection, protect the PCM before unplugging it. Before disconnecting the PCM connector, jump the SCS line with the HDS and wait more than 1 minute. Then set up the circuit check by disconnecting the alternator connector, PCM connector A, the shutter grille connector if equipped with the shutter grille, the 12 volt battery sensor connector, and the DC-DC converter connector if equipped with auto idle stop.
Check the LIN wire for opens and shorts
With IG Mode OFF, check the LIN battery-sensor line for an open according to the terminal table. Normal is less than 1 Ω. Then check that same LIN line for a short to ground, again with IG Mode OFF. Normal is more than 1 MΩ. If either result is abnormal, treat it as a circuit problem before moving on to component conclusions.
Isolate components on the shared LIN line
Once the external circuit is normal, move into the component-connected-to-LIN inspection. Use the same PCM protection step first: before disconnecting the PCM connector, jump the SCS line with the HDS and wait more than 1 minute. Then disconnect the alternator connector, PCM connector A, shutter grille connector if equipped, 12 volt battery sensor connector, and DC-DC converter connector if equipped with auto idle stop. With IG Mode OFF, reconnect the PCM, shutter grille, 12 volt battery sensor, and DC-DC converter connectors one at a time while checking the circuit. Normal is not shorted. If the fault appears when a specific part is reconnected, the problem is with the part that shorted the line when it came back into the circuit. This isolation routine can be useful early because it covers multiple items, but if it fails, continue with the individual inspections to identify the failed item cleanly.
Alternator inspection logic
After the external circuit is normal, move to the alternator inspection. There is not a direct standalone test for the alternator in this path, so the diagnosis is made through the related checks. Run the confirmation procedure again and look for the companion alternator communication result without treating the code name itself as the repair. If that check is normal, the path points to a problem with the alternator. If it is abnormal, the path points you back toward other related components.
Alternator internal circuit and final PCM call
If you continue into the alternator circuit inspection, again start by jumping the SCS line with the HDS and waiting more than 1 minute before disconnecting the PCM connector. This inspection also assumes the external circuit has already tested normal. Disconnect PCM connector No. 1, the DC-DC converter connector if equipped with auto idle stop, the shutter grille connector if equipped, and the 12 volt battery sensor connector. Then, with IG Mode OFF, perform the alternator internal circuit inspection at the disconnected 12 volt battery sensor connector male terminals. Normal is not shorted. If that inspection is abnormal, the problem is with the alternator. If the other inspection items all showed normal results, the remaining call in this diagnostic path is a problem with the PCM.
Takeaway
The main thing with P16E2 is to work from simple power-terminal checks, to the LIN wiring, to shared-line component isolation, and only then to alternator or PCM conclusions. Do not condemn a module just because the code is present; make the circuit prove it. For more diagnostic training, visit stepdiagnostics.com.
Final check
P16E2 is often best approached by proving the power-terminal condition, the LIN circuit, and the connected components before making an alternator or PCM call.
For more guided automotive diagnostics, visit STEP Diagnostics.
