What’s an ignition control module anyway?
Ever wondered what’s actually firing up your engine when you turn the key? That’s the ignition control module – or ICM, if you want the short version. Basically, it’s the brains behind making your spark plugs fire at just the right moment. Every time you cruise along Wairere Drive or crawl down Heaphy Terrace in morning traffic, your ICM is working away, switching the power on and off to the ignition coils. That’s what gives you those sparks needed to ignite the fuel and get the motor running smoothly.
When it’s working good, you might forget it’s even there. But in Hamilton’s mix of frosty mornings and hot, dry summer afternoons, your ICM does a lot of hard yards. Doesn’t matter if you’re driving a Honda CR-V, a Peugeot 308, or even a Nissan Serena – they all rely on that ICM to keep things firing right.
Most of the time, you’ll find the ICM tucked away in the distributor housing, not far from the ignition coil. When it goes bung, your car can start running rough, misfiring, or just plain not starting. That’s when it’s time to bring it in and get it swapped out. It’s a pretty common job for us – we see everything from Suzuki Swifts owned by students commuting from Cambridge, to Mazda Biante vans doing the school run between Rototuna and Te Awamutu.
Learn more about how the ignition works >
What knocks out an ICM?
- Dodgy wiring – If you’ve got frayed wires, loose plugs or a bit of a short happening, the ICM might not get the power it needs, or could get zapped and pack up altogether. Saw this just last week in a VW Golf coming down from Tamahere. One connection rattled loose, caused a fair bit of drama.
- Open circuits – If something goes wrong at the spark plug end, all that voltage has to go somewhere. Seen it blow the ICM more than once, especially on older Hyundais or a Toyota Estima or two.
- Overheating – Sitting in traffic on Victoria Street in the middle of summer, or stop-start from Dinsdale to Hillcrest, things can get toasty under the bonnet. If your ICM gets too hot, especially as they age, they can fry themselves. European cars, like the odd Alfa around Hamilton, are a bit more prone to this too. Old heat shields just don’t keep up.
How do you know your ICM’s playing up?
- Misfiring – Feels like the car’s shuddering, or not quite catching right – maybe especially when you’re leaving a roundabout on Peachgrove Road. Often it’s the ICM not telling the coils to spark.
- Losing power – If you’re putting your foot down out by Morrinsville and the car’s not picking up like it should, dodgy ignition might be the cause. You’ll likely see your fuel economy dropping too.
- No start, no go – Worst case, car just won’t fire up at all. No spark, no start. Pretty common on older Subarus and the odd imported hatch.
- Random stalling – Sometimes the ICM plays up only when it’s hot, cuts out while you’re driving, then comes back when it cools off. Had a client’s Ford Mondeo stop halfway up the Tainui Bridge the other day for exactly this reason!
Need your ICM replaced in Hamilton?
If you reckon your ignition control module is on the fritz, we can sort it here at Grimmer Motors. Doesn’t matter if you drive a city runabout or a van that gets between Ohaupo and Gordonton every day. One of our techs will check it out, work out if it’s the ICM or something else, and get the right bit in there so you can get back on the road, no more mucking around.
We do all sorts of ignition repairs, not just modules. If you need a battery swap, spark plugs replaced, or ignition coils sorted, we’re your crew for anything to do with your car not firing right.
Just a heads up – we’re a proper workshop, not a parts shop. We don’t usually just sell you the bit over the counter. If you bring your car in, we’ll diagnose it, get the right part, and fit it for you, no stress.