Error Code P1298 is defined as Electric Load Detector Circuit High Voltage. This means the ELD (Electric Load Detector) is getting high input voltage.
This error code is a manufacturer-specific trouble code, meaning it does not appear to all vehicle makes and models with OBD-II system or vehicles made since 1996 up to present. Rather, it applies to select vehicle manufacturers, most commonly among Honda vehicles like Honda Accord, Honda Civic, and Honda CR-V. Other manufacturers with the same error code may have different specifications on the definition, troubleshooting, and repairs for this code.
The Electric Load Detector works by monitoring the amount of current that the charging system is using, so it can determine how much voltage needed to charge the battery. If the voltage input is too high, it signals the PCM that something is not right with the ELD, activating the Check Engine light and registering the code in the process.
As with other error codes, this code sets the Check Engine light and registers the error code. Usually, there are no other noticeable symptoms. In some cases, however, the engine may suffer rough idle, especially when the vehicle settles down or transitions from high throttle to rest, or the engine feels like it’s misfiring.
There are multiple reasons for this code to appear, some of the most common causes include:
- Faulty Electric Load Detector
- Faulty PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes)
- Open or shorted Electric Load Detector Harness
- Poor electrical connection in Electric Load Detector Circuit
How to Check
The first thing you can do to diagnose this problem is to reset the PCM. Pull the number 6 fuse for 10 seconds and then put it back in. Then, start the engine and turn on the headlights, check for the same code. If the code is not thee, that means you have an intermittent failure. Next, check the connections at the ELD.
If the code comes back, turn the off both the headlights and the ignition. Disconnect the ELD 3P connector, which is located behind or underneath the under hood fuse box.
Next, turn on the ignition and measure the voltage between the ground and the ELD 3P connector through the terminal no. 1. It’s the black/orange wire. Backprobe that on the harness connector.
If there is no battery voltage, then check the no. 4 fuse. If the fuse is ok, repair the open in the wire between no. 4 fuse and ELD.
If there is a battery voltage, turn off the ignition and then connect the ELD 3P connector terminal no. 3 to the body ground with a jumper wire. No. 3 terminal is the green/red wire. Again, back probe that with a pine and connect the jumper wire the pin.
Next, disconnect the PCM connector E (31P) and then check for continuity between body ground and the PCM connector terminal E15. It’s the green/red wire at terminal 15.
If you don’t see continuity, then repair open wires between the ELD and the ECM E15.
If there is continuity, check for continuity between the ELD 3P connector terminal no. 2 and body ground. It’s the black wire.
If there is no continuity, repair open wires between the G201 which is ground connection and the ELD.
If there is continuity, reconnect the ELD connector as well as the PCM. Start the engine and allow it to idle.
As you measure the voltage between the PCM connector terminals A24 (brown/yellow wire) and E15 (green/red wire), make sure you turn the headlights on high. Check whether the voltage drops.
If the voltage does not drop, replace the ELD
If the voltage drops, then you need to update the PCM or replace it.
How to Fix
This error code is easy to repair, but of course, you need a thorough diagnosis as enumerated above. Some of the most common fixes are:
- Replacement of the Electric Load Detector
- Update or replacement of the PCM
- Repair open wires
- Repair or replace Open or shorted Electric Load Detector records
- Repair poor electrical connection in Electric Load Detector Circuit
For Honda vehicles, there is a factory service bulletin for Honda models such as 2001–2005 Honda Civic, 2002–2004 Honda CR-V 2001-2005, and Honda Civic 2002-2004.