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gregoryk
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20 Posts
Discussion Starter #1
I took my 05 Elise out today for the first time since last Oct. After a few miles the engine management light on the dash came on so I took it over to the local toyota specialist. He couldn't locate a problem, turned the warning light off and said sometimes after sitting gas could be the problem and not to worry about it too much unless the light came back on and started blinking.
I went out on the Pa. Turnpike and took it up to just over 6k rpms and it bogged badly when the cam came on and the engine mgmt. light came back on. It ran fine when I put it away last fall, but once when I started it up over the winter it idled roughly. Next time I started it it ran fine.
Today I added injector cleaner and octane booster. Not sure what the next move should be. Any thoughts or suggestions?
 

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2005 Lotus Elise
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54 Posts
I would check the plugs too. Make sure they are gapped correctly as well

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733 Posts
I'm not sure how best to diagnose that fault. but this is consistent with your observation that high enginee speed results in bogging; if there's problems in the air flow path, the engine can't rev freely.

the service manual suggests faulty valve timing (i.e. timing chain misalignment) or VVT actuator faults. i think the timing chain is unlikely to be the trouble, unless the tensioner has failed. the vvt mechanism relies on oil pressure and i think it's active at all engine speeds.. could you confirm that it's working via an obd tool? i mean, monitor vvt position while you drive with obd mode 0x22, pid 0x208?

Code:
Camshaft Timing Control (VVT) P0011
 P0012
P0076
P0077
P0011 Camshaft Position – Timing Over-Advanced or System Performance
P0012 Camshaft Position – Timing Over-Retarded
P0076 Intake Valve Control Solenoid Circuit Low
P0077 Intake Valve Control Solenoid Circuit High
Description
The Variable Valve Timing system (VVT) on the intake camshaft can vary the timing by approximately 25°. The 
camshaft relative position is varied by a system of vanes mounted on the drive end of the camshaft. The VVT 
oil control valve modulates a spool valve position in accordance with the drive signal duty cycle, this in turns 
controls the oil pressure applied to the vanes. A 50% duty cycle applied to the valve will hold the valve current 
timing by preventing oil flow from the VVT controller housing, a duty cycle less than 50% will retard the valve 
timing, a duty cycle greater then 50% will advance the valve timing.
Component connections
Sensor Connector Description ECU Pin ECU Connector
1 Battery Voltage - -
2 VVT Oil Control Valve 49 (J3) 52 Way (Right) '06 M.Y. in brackets
 
P0011, P0012
Monitor: Continuous
Enable Criteria:
•	 Engine running > 30 secs
•	 Coolant temperature > 60°C (140°F)
Disable Criteria:
P0116, P0117, P0118 – Coolant temperature fault codes
Potential failure modes:
•	 Static valve timing is incorrect
•	 VVT camshaft actuator failure
•	 VVT valve stuck open / closed
 

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gregoryk
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20 Posts
Discussion Starter #9
I don't have access to an obd tool. I can check with the local Toyota specialist on Mon.
Thanks very much for the help. I'll keep you posted.
 

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gregoryk
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20 Posts
Discussion Starter #10
Problem Solved!! After reading over some old posts here on the forum, I found other members with the same P0012 code alert who had previously jump-started their Elise (as I did). Jumping the battery blows the 7.5 A R6 fuse that handles VVT and the 5A R4 fuse that handles the ECU battery feed. Both are located in the second fuse box to the right of the ECU. Replaced both fuses and turned off the warning light. Went for a short ride and the VVT is now working as it should.
Thanks everybody for all the help. This forum is a lifesaver!!
 

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665 Posts
Problem Solved!! After reading over some old posts here on the forum, I found other members with the same P0012 code alert who had previously jump-started their Elise (as I did). Jumping the battery blows the 7.5 A R6 fuse that handles VVT and the 5A R4 fuse that handles the ECU battery feed. Both are located in the second fuse box to the right of the ECU. Replaced both fuses and turned off the warning light. Went for a short ride and the VVT is now working as it should.
Thanks everybody for all the help. This forum is a lifesaver!!
This makes no sense. I run a 15 oz battery, which basically only starts the car if it's already warm and lubed (i.e. just protection vs stalled on course or something). Consequently I jump the car with a lithium jump starter (using a in-cabin plug that I fabricated) EVERY time I start it. Fuses are unlikely to blow just due to a jump start unless you hooked up the wrong polarity or used a wrong voltage source.
 

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4,415 Posts
This makes no sense. I run a 15 oz battery, which basically only starts the car if it's already warm and lubed (i.e. just protection vs stalled on course or something). Consequently I jump the car with a lithium jump starter (using a in-cabin plug that I fabricated) EVERY time I start it. Fuses are unlikely to blow just due to a jump start unless you hooked up the wrong polarity or used a wrong voltage source.
It is common enough that I was going to suggest looking at fuses until I saw he fixed it, haha. Owner's have also reported it happening when bump-starting, so no chance of reversed wires there.
 

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I had a problem of fuse R6 failing twice over a period of a couple of months. I did a close inspection and discovered the wire that goes up to the vacuum switch sitting atop the air box had chafed through and shorted against an adjacent bracket. I replaced the fuse and jiggled the wire and sure enough the same fuse blew. I repaired the wire and never another issue... at least so far for about another 25,000 miles.
 

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665 Posts
It is common enough that I was going to suggest looking at fuses until I saw he fixed it, haha. Owner's have also reported it happening when bump-starting, so no chance of reversed wires there.
Wonder if there's a model year or euro/us dependency there... mine is an early 2005 (US)
 

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Wonder if there's a model year or euro/us dependency there... mine is an early 2005 (US)
Mine is also an '05 but the time I experienced this was due to inverted polarity several years ago. The bumpstart issue is what makes me thing there's more to it than carelessness.

Fun side note, I was debugging a car one time someone else wired up. It took me something like three solid days and an oscilloscope to finally find that the inductive crank sensor was wired backwards. Being inductive, it swings from positive to negative, so being backwards shouldn't matter but it still managed to reset the ECU as soon as the rpms hit around 600 (at that point the signal was greater than battery voltage).

Electrical systems are weird.
 
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