Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Ignition Coil Relay Circuit Test (MDX)
2004 Acura 3.5RLSECTION Ignition Coil Relay Circuit Test (MDX)
NOTE:
Check No. 46 (15-amp) fuse in the under-hood fuse/relay box and No. 8 (15-amp) fuse in the under-hood subfuse box. Replace if necessary and follow procedure below.
- Remove ignition coil relay from relay block. Connect a fused jumper wire to relay terminal No. 3 and battery voltage. Connect a ground wire to relay terminal No. 4 and negative battery terminal. See Fig 1 . There should be continuity between relay terminals No.s 1 and 2. Disconnect ignition coil relay from battery power and ground connections. There should be no continuity between relay terminals No. 1 and 2. If either test has results other than as specified, replace relay. Go to next step.
- With relay disconnected, measure voltage between ground and relay connector terminal No. 1. If there is battery voltage, go to next step. If there is no voltage, repair open in circuit between relay connector terminal No. 1 and No. 8 fuse in under-hood subfuse box.
- With relay disconnected, measure voltage between ground and relay connector terminal No. 4. If there is battery voltage, go to next step. If there is no voltage, repair open in circuit between relay connector terminal No. 4 and No. 46 fuse in under-hood fuse/relay box.
- Disconnect ignition coil 3-pin connectors. Check continuity between ignition coil power relay connector terminal No. 2 and each coils connector terminal No. 3. If there is continuity, go to next step. If there is no continuity, repair open circuit between ignition coil power relay connector terminal No. 2 and suspect coil(s) connector terminal No. 3.
- Check continuity between ground and ignition coil power relay terminal No. 3. If there is continuity, repair short to ground between relay connector terminal No. 3 and PCM. If there is no continuity, repair an open in circuit between relay connector terminal No. 3 and PCM.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.