2005 Suzuki King Quad C12 code

[DaDolt]

So, I found myself in the only 5' deep water hole in Moab with the King Quad. Before I could get off it swallowed water at idle and died. The river water was not very clean. I pulled the plug and pumped the water out of it with the starter. I cranked on it and it popped for a second and then was done. Towed it back to the trailer. When I got home I checked the compression and it had none. I have a factory service manual. Disassembled and found the rings stuck in the piston lands. New rings and back together. I try to start it and get a C12 code CKP - crank position sensor. Troubleshoot and find it to be shorted. Installed aftermarket CKP, still get code. Check voltage on new CKP and only get 4.5V, manual calls for 5V minimum. Pulled every connector apart on vehicle and cleaned. Have continuity from CKP sensor side of connector to ECM harness. Install a known good ECM from another 2005 KQ I have. Vehicle fires and I let it run for 10 minutes. Shut it down and put the original ECM in and get a C12 code again and won't fire. Put the known good ECM back in and get C12 and no fire. Tested both ECM's in the other KQ and runs well on both ECM's. Installed a used stator and CKP. Still get a C12 code. Check used stator, 200 ohms and 6.5 V out of the CKP at the ECM harness. Checked ground at ECM harness and it is good. Checked spark with spark plug and without, none. Checked resistance and peak voltage on coil and it is in spec.

This thing has me baffled. All of the electrical possibilities seem to check out. Might be far fetched, but could the rotor key have sheared when it shut down suddenly when the cylinder filled with water? I know rotary lawn mowers can shear the flywheel key when the blade stops suddenly from a rock or stump. If the key is sheared and the flywheel is out of time by a few degrees could this be giving the C12 code? The voltage output is correct but at the wrong crankshaft position (wrong time).

[Mech]

I think those computers are pretty simple software and will probably only set that code if the sensor is actually not getting it's signal to the ecu. On modern things they do calculate and deduce bad out of range readings, and things like a key or cam being out of time, but as far as I know it's not done on those. Have a read up and you may find they do deduce things like that though. Things are improving all the time.

It started and ran with the temporary ecu, so the crank key presumably is ok. There's no reason the crank sensor should short because of the dunking, and a new aftermarket gave the same code.. 

Have you checked/cleaned, or disconnected the kill switch and ign switch ?

The manual should have a list of conditions that cause the code, and what the ecu does in response.. such as switch to base figures to limp home or shut right down.. If you read those really carefully you may get some ideas..

You sound pretty onto it.. you'll get it ..  But I'll have a read up later and have a think about it and get back to you..

[Mech]

Well I had a look in a slightly older model and the trouble codes are only set by missing connections. The ecu does not deduce faults.

The criteria for the c12 code is "The signal does not reach ECM for 3 sec. or
more, after receiving the starter signal". And it says the fault will be...  "CKP sensor wiring and
mechanical parts."...  It would seem you have an intermittent wiring disconnect most likely.  Since you have been changing things and getting differing results, it's a guess that there is a broken wire on the end of some wire where it goes into it's terminal.. or a wire broken inside the insulation somewhere.. I'd definitely be wriggling the wires individual(gently bending them) feeling for one that's too flexible.. broken copper and only plastic holding it together.

Hmm.. bad cut.. It actually says..

"CKP sensor wiring and
mechanical parts.
CKP sensor, lead wire/coupler
connection."..

[Mech]

After thought..  Since it's happened since the water, and before you disturbed it.. perhaps it's corroded terminals, corroded or eaten by the electrical current.. It would pay to work the rubber seals out of the plugs with a pin, and then get the terminals carefully out of their housings, and check the crimp on terminals don't have dirty connections to the wire.

[Mech]

And, since you are I'm sure interested..  All the other sensors get over ridden and set at arbitrary figures if they play up so you can limp home. The CKP is the only one that kills the starting.

It also warn that metal flakes on the crank sensor or flywheel will stop the signal. It only takes the tiniest bit of metal to bridge the gap between flywheel and sensor to short the magnetic flux. It might be worth checking that carefully... A real careful wipe with a rag mostly grabs rust/metal flakes.

[DaDolt]

I pulled the strain relief out of the ecm connector. While cranking I twisted the ecm in all directions and got it to fire. I bought a new OE wiring harness and now it runs. Having continuity does not nessisarily mean there is an adequate circuit to carry the watts required in the circuit. Thanks for your help!

[AussieKingQuad]

I've got what looks like exactly the same problem. king quad 450, 2008 model it was overcharging 17-20V so I changed the voltage rectifier and fixed the overcharging, it ran fine for months. on a later scheduled service I noticed the earth wire on the coil had lost its insulation going back 30cm from earth terminal ring, so un-taped a section of the loom and replaced the coil earth wire.

but now I have code c12, ( no spark ,no injection pulse) my mechanics diagnostic tool gave 3 codes -Engine coolant/oil temperature malfunction , -Crankshaft position sensor A circuit, -Ignition coil A circuit malfunction.

CPK gives 4.7V and sensor resistance white -blue =217 ohm ( in range) white to ground =open ( correct)

Ignition Coil peaks just below the recommended 80V (but I'm thinking at starter motor crank speed it wont be as a high as specified)

primary and secondary ignition coil windings resistance are both in range.

untaped entire loom , visually inspected every wire, all looks good.

I have done continuity tests on all relevant wires

after hearing of DaDolt's success, i pulled the strain relief out of the ecm connector and while cranking I twisted the ecm in all directions BUT didn't get it to fire.

I don't have spare king quad like DaDolt but thinking of buying one, I'm scared if I do buy spare king quad and swapped out the ecm's I could blow the donor ecm if I have a fault like an earthed wire?

[Mech]

I'd be suspecting and inspecting all the power supplies and all the earths to the ecm and everywhere else at all.  The earth wires particularly.

The old earth wire.. was that melted off insulation or rat eaten insulation ?

[Mech]

Actually.. Second reading. You say it has the right peak coil voltage..  and the coil's resistances are correct.. but there's no spark.. So either the coil, the spark-plug, or the lead, have a short or an open circuit..

Have you cleared the trouble codes ? I haven't read the manual but those might be historical codes.. They might have been set by you working on it, or some intermittent thing that you've now fixed.

[AussieKingQuad]

the earth wire on the coil had lost its insulation (due to melting) going back 30cm from earth terminal ring, I suspect this is from the voltage regulator putting out too higher voltage.

I miss understood what my mechanic told me. Ignition Coil peak volt test is 0.06V - not below 80v as I miss understood

but the primary (0.5ohm) and secondary (15.35kiloohm) ignition coil windings resistance are both in range.

 

[Admin]

@AussieKingQuad please post all manuals in our downloads section. I moved this one you added there. We also have:

 

[Mech]

15 hours ago, AussieKingQuad said:

I miss understood what my mechanic told me. Ignition Coil peak volt test is 0.06V - not below 80v as I miss understood

but the primary (0.5ohm) and secondary (15.35kiloohm) ignition coil windings resistance are both in range.

Well that seems like the ecm isn't putting the power out. I'd rechcek the crank position sensor, the coil resistances, and the power and earth wiring to the ecm and then the conclusion is that the ecm is crook..

[Gwbarm]

If the coil got hot enough to melt the insulation off i am surprized it is still functional.