What this code means
B1080 may indicate that the relay control module sees the ignition-one power input differently than the ignition-one status being reported by the body control module over the body-
What the vehicle may do
- The vehicle may show inconsistent body electrical behavior related to ignition mode.
- The code can also be stored with limited obvious symptoms.
Possible fault areas
- A possible IG1_METER circuit issue.
- A possible power supply circuit issue.
- A possible body control module input or reporting issue.
- A possible relay control module signal comparison issue.
Diagnostic path
Open on B1080
On this 2016 to 2024 Honda Civic with the 1.5 turbo, B1080 is an IG1 power-supply plausibility code. In plain language, the relay control module may be seeing the ignition-one input differently than the ignition-one status being reported over B-CAN by the body control module. The vehicle may have body electrical behavior that seems inconsistent with ignition mode, or it may simply store the code without an obvious symptom. The possible fault areas here are the IG1_METER circuit, the power supply side of that circuit, the body control module input, or the relay control module’s comparison of those signals.
Set up the diagnosis
Before getting into the circuit, start with the basic system checks and follow a structured diagnostic approach. If other codes are present, check what they mean first and handle the B-CAN diagnostic path before treating B1080 as a stand-alone fault.
Understand the fault logic
The logic is a comparison check. The relay control module is watching its IG1 signal input and comparing that against the IG1 signal coming from the body control module over B-CAN. If those two do not agree for a set time or more, the relay control module stores B1080. So the test is not just looking for power. It is looking for whether the hardwired IG1_METER circuit makes sense compared with what the networked body control module is reporting.
Reproduce the monitor conditions
Turn the vehicle to ON mode, then wait for at least 6 seconds. That gives the module time to run the comparison before you judge the circuit.
Check the IG1_METER circuit
With IG mode ON, perform the IG1_METER circuit inspection at body control module connector A, the 66-pin connector, using the female terminals. The normal condition for this check is 12 V battery voltage. If the IG1_METER circuit check is abnormal, treat it as a circuit problem. If the power supply part of that check is abnormal, continue with the power-supply inspection for that circuit to locate the failure before making a call on the module.
Interpret the result
If the IG1_METER circuit inspection is normal, the diagnostic path points toward a problem with the body control module. If it is abnormal, stay on the circuit path and do not jump straight to a module conclusion. Pause, recheck the earlier diagnostic path, and avoid guessing if the next circuit-locating details are not available in front of you.
Close and takeaway
The takeaway on B1080 is simple: prove whether the relay control module’s IG1 input and the body control module’s IG1 status can agree. Start with system-level checks, reproduce the ON-mode condition, check the IG1_METER circuit for 12 V battery voltage, then separate a circuit fault from a body control module concern based on that result. After any correction, verify the repair and confirm the code stays gone. For more diagnostic training, visit stepdiagnostics.com.
Final check
B1080 is often approached as a plausibility check between a hardwired IG1 input and the body control module’s networked IG1 status.
For more guided automotive diagnostics, visit STEP Diagnostics.
