99 SL PO340 & 341 codes.

[Belarus99]

I have replaced the plugs and wires. Still getting the codes. I checked ohm reading on both coil packs and one was 7.2 and other was 7.3. The troubleshooting guide on this site says between 8 and 15. Would the 7.2 cause the 340 and 341 codes. After reading some more threads on here I noticed I should have BKR4ESA11, the plugs I put in were BKR5ESA11. Would this make a difference. I removed the coil packs and the control module and sanded and wire brushed where it mounts to transmission. If I do need new coils is there a brand that is preffered. I have seen on other threads that some high performance ones also cause problems.

[OldNuc]

The BKR4ESA-11 are for the SOHC engine which I believe is what you have. The wrong plug will not help, that is for sure.

Check your firing order. The diagram below is the way the cylinders and coil towers are numbered from your left to right as you look at the engine.

1 2 3 4 engine

4 1 2 3 coil towers

What this is telling you is that the #1 plug is connected to the 2nd from the left coil tower, marked #1 in the diagram above.

Also, the #1 and #4 wires should run next to each other in the wire clips from the coil to the head.

I do not think the resistance is your problem.

[rc1488]

Brass ECTS? Replace it if it is not.

[saturnbandit]

try a used coil pack from a junkyard, they are cheap. check your firing order

[Belarus99]

I checked firing order. I replaced ECTS. I replaced bolts holding on coils. The code comes in almost instantly after starting.

I checked the ohms on the plug wires and they are right around 1000 ohms each is this within proper specs? The ones I took off were around 8000 to 10000ohms. I ordered the other NGK plugs for the SOHC. I had put in the ones for the DOHC. I have also bought a used ignition module and coils from ebay to try.

[Belarus99]

Does anyone have suggestions on wires for this if the 1K ohms is really a bad things for these finicky P0340 codes. Thanks

[OldNuc]

The P0340 is a pending code. All it means is you will have an active P0341 with one more missing pulse. It is only significant if there is also no active P0341. It is the 341 to be concerned about.

Next things to try are the proper plugs, new wires and replacement set of coils and ICM. As to the wires go buy a decent quality mid priced plain direct fit ignition wires. I believe Duralast has been deemed OK. The wires you have now are showing funky resistance. The shortest wire will be about 1/2 of the resistance of the longest. And the sum of #2 + #3 will be approximately the same as the sum of #1 + #4 Or (R-1)+(R-4)=(R-2)+(R-3).

Based on your reported symptoms I would suspect the ICM or the wire between the ICM and PCM. It is important that the socket and plug at the ICM be clean, dry and grease free. Use CRC Electrical Connector cleaner to flush them out. Do not use brake cleaner!

[SLCraig]

Just had a 341 myself.. was a bad coil. check for grounding, clean plugs, etc.

[rc1488]

When changing coild/ignition modules, clean the backing plate where it mates to the tranny.

[Belarus99]

Its fixed. I bought a used ICM and coils off ebay for $24 including shipping. Put them in and no more code. Drove it around for about 30 minutes to get all systems ready after clearing codes and she passed inspection with no problems. I picked up the BKR4 NGK's today and will replace the 5's with the 4's.

THANKS for all your help. I was starting to get frustrated , but you guys pointed me in the right directions. What would we do without the internet?