Toyota Repair: 01 Toyota Sienna, 6 igniter DTCs, engine harness, scantool

Question
Hello,

I have a customer that I've dealt with for years, they have an 01 Sienna 3.0 vvt.

When the engine warms up it will set DTCs for all 6 igniters (p1300,1305,1310,1315,1320,1325) regardless of load (in drive, neutral or when brake/torqueing). It is a function of temperature as it ids fine when cool, with a definite misfire over 2500 rpm.

I checked the flowchart for P030 and all tests led to PCM.


A 2nd test unit was obtained, though there was no change in the condition. I obtained the diagram for engine controls and attempted to test all circuits relating to the coils, though I don't see a wiring issue changing with temp. I see the white/black igf circuit is in series, this may result in all igniter DTCs if a coil was bad when temp increases.

We also tested backpressure and the cats were within specification. I am inclined to think a coil is intermittent, dragging the other 5 down but we shipped it as the customer needed quick results.

The local Toyota dealer wanted over 500 for a diag with no conclusive results, they say ECM or engine harness; I think the ECM is OK due to our results with the swapped in part; and a wiring issue would not be temperature related.

We are considering revisiting this, what are your thoughts?
Jeff


Answer
All of the coils can not be bad so there is a problem common to all of them, have you checked the ground wiring for the coils? Could be a bad ground. It is possible that one bad coil can cause a random misfire, try clearing the codes then drive it with a diagnostic scantool attached and see if any pending codes show up before the check engine light turns on, this may pinpoint which coil is failing first, if they the same codes come up simultaneously again then I think it has a wiring issue.