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Have a '98 Avalon in the shop with a no-start and code P1300 (igniter circuit malfunction).Initially, we were able to get it to run by unplugging coil #6. We installed new plugs, coils, and wires, but now it is still a no-start. We initially had intermittent spark on cylinders 6 and 3, and now there is no spark at all on those cylinders. The remaining cylinders have spark while cranking.So far I have:
Verified wire integrity from the coils to the igniter and from the igniter to the ECM.
Verified all grounds are good.
Scoped the IGT and IGF signals at the igniter.
Scoped the crankshaft position sensor and the waveform looks good.
Visually inspected the crank reluctor wheel and found no issues.
Scoped the camshaft position sensor and the waveform looks good.
Visually inspected the cam timing components and found no issues.
Verified base timing is correct.
Swapped in a known good igniter with no change.
Ruled out bad coils multiple times.
When scoping at the ECM, I can see the IGT trigger signal for the problem cylinders, but I do not see IGF confirmation. On the cylinders that are firing correctly, I see both a good IGT trigger and IGF confirmation.I may be interpreting this incorrectly, but if I have an IGT trigger from the ECM to the problem cylinders, why would I not see an IGF confirmation? Since the other cylinders are generating IGF feedback normally, why would it be missing only on these cylinders?At this point I'm starting to suspect a bad ECM, but in my experience ECM failures on Toyotas are pretty rare. Has anyone run into something similar or have a better diagnostic procedure I should follow before condemning the ECM?
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