Hondata wrote:The ELD input only provides an idle up for the engine. It doesn't change the alternator control / output.
Thank you for your response. Actually, the FR circuit between the Alt and ECM B Connector Pin 13 is responsible for controlling engine idle. Not the ELD sensor. I put some additional information below explaining how the Honda Dual Charging System operates (just as an FYI).
That aside, I have found some discrepancies in the Hondata wiring diagram
. I point these out not to be a 'detail freak'
, but because it's creating some issues during the troubleshooting process as outlined in the Honda manual (2004 Acura RSX Type S).
The issue I'm having begins with the first step in the Honda troubleshooting procedure outlined in the manual... Charge Indicator Lamp Test
. My issue is there is no output (or pin for that matter) on C101 pin 8. The wiring to the lamp (which I installed per this diagram) is installed, but the Honda ECU does not provide any trigger there for AltL (Blue/White wire). I did apply a ground to pin 8, and the lamp on my dash lights just fine, so my wiring is correct... but the wiring diagram is incorrect.
Here are the Honda PRB ECM pinouts out of the manual.
They didn't label the connector above very well, so here's another reference to it with better descriptions.
Connectors C & D below are not used (A/T only)
So there is a discrepancy in the wiring diagram for proper operation of a charge indicator lamp. I'd like to fix that, but I'm pretty sure it's not the root cause of my charging problem. To that, here is the Honda Dual Charging System diagram from the manual. I've correlated the Alternator pinouts to the ECM connectors for reference.
Terminals & Modes
The voltage regulator utilizes five terminals: Ignition (IG), Control (C), Field Reference (FR), Battery, (B) and Lamp (L). The B terminal is the high current circuit that's responsible for charging the battery. The other circuits are located in a single connector and are responsible for controlling the voltage regulator located within the alternator.
The IG circuit is crucial to proper charging system operation. Turning the ignition switch to the Run position will send source voltage to the IG terminal, which is required to energize the voltage regulator.
The C circuit is responsible for controlling the charge mode (based on the voltage on the ELD circuit). So indirectly, the ELD controls the charge rate (High/Low). The voltage regulator sends a voltage to the ECM through the C circuit. Depending on the charging systems needs, the ECM either holds the voltage high to signal the high output mode, or it pulls the voltage low to signal the low output mode. When the circuit C voltage is pulled low by the ECM: the charging voltage at the battery will range from 12.4 - 12.9V. The ECM uses the low output mode when the engine is starting or if all of the following parameters are met:
electrical Load below 15 Amps (varies with vehicle)
vehicle speed between 10-45 mph or at idle while in drive
engine speed below 3,000 rpm
coolant temperature above 167°F (75°C)
A/C Switch Off
intake air temperature above 68°F (20°C)
Outside of these parameters, the ECM will hold the voltage on the C circuit, which will place the charging system in the high output mode. In this mode, the charging voltage at the battery will range from 14.4-14.9V.
Note: The ELD circuit is pretty easy to fool. Pull the ELD out and use a 600-800 ohm resistor to ground and the ECM thinks the car's current load is high (forcing C to keep the alternator in high mode).
The ECM uses the FR circuit for field rotor status to be able to change engine idle speed. If the alternator is under high load, the ECM will increase idle speed. While the engine is running, the ECM sends 5V to the voltage regulator through the FR circuit. When the field rotor is on, the voltage regulator will pull the voltage down and when the field rotor is off it will hold the voltage high to around 6vdc.
The charging system utilizes the L circuit to inform the driver of any charging system faults. Over the years Honda has used two methods for illuminating the charge warning indicator lamp. On older models, the L circuit directly provided ground for the warning lamp if a problem was present. If everything was in spec, the voltage regulator removed the ground by providing positive source voltage on the L circuit.
However, on late model vehicles, the ECM sends source voltage to the L circuit. If a problem occurs, the voltage regulator will pull the voltage on the L circuit to ground. If this occurs, the ECM will sense that the signal voltage has been pulled down and it will then send a “charge warning lamp on” signal through the CAN bus network to the gauge control module. In this case, the gauge control module will directly switch the indicator lamp on.
So the first question is, since the AltL signal (Ground) is not on C101 pin 8, where shall I connect the charge lamp to?
The second (or original question was), what exactly does the ELD enable/disable in K Manager actually do? I think the answer is 'It ONLY quashes ELD related codes.' and has nothing to do with what charge mode the 'C' circuit will output on the ECM Connector B pin 18.
Sorry for the long response, but I would like to address the charge lamp issue. I'm hesitant to T-tap the Blue/White AltL wire off the ECM Connector B pin 10 to the lamp until I hear back from Hondata. I don't want to cause any damage to the ECM. Maybe disconnecting it from the ECU and connecting it to the lamp circuit?