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Location:
Sydney
Registered:
January 2003
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Error code 78
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Fri, 21 October 2005 02:02
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Upon entering diagnostics mode i get 7 flashes followed by 8 flashes. Error code 78 does not seem to be in the service manual.
On a bigport 4AGE. Anybody have any ideas ?
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Registered:
October 2005
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Re: Error code 78
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Fri, 21 October 2005 02:32
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I'd be thinking ecu :/
I havent seen it mean anything either, unless you're confusing 2 codes as 1.
25
34
43
52
^ all = 7
26
35
53
^ all = 8
Look closer.
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Location:
Sydney
Registered:
January 2003
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Registered:
October 2005
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Re: Error code 78
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Fri, 21 October 2005 02:40
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4 second break you say? Sounds like the gap between 2 codes.
In which case, you may have 2 single digit codes.
http://www.off-road.com/toyota/tech/codes/
7=
--THROTTLE POSITION SENSOR SIGNAL
--OPEN OR SHORT IN TPS SIGNAL
--TPS SENSOR
--TPS SIGNAL/CIRCUIT
--ECU
8=
--INTAKE AIR TEMPERATURE SENSOR SIGNAL
--OPEN OR SHORT IN INTAKE AIR TEMP. SIGNAL
--INTAKE AIR TEMPERATURE CIRCUIT
--INTAKE AIR TEMPERATURE SENSOR
--ECU
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Location:
Sydney
Registered:
January 2003
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Re: Error code 78
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Fri, 21 October 2005 02:47
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I think your right!
Ok for the 4AGE going from the service manual:
7 can be only
25 - Air-fuel ratio lean malfunction
43 - Starter Signal
52 - Knock sensor signal
8 can be only
26 - Air-fuel ratio rich malfunction
53 - Knock control signal in ECU
So it must be either 25 and 26 or 52 and 53. Didnt know mine had a knock sensor.
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Registered:
October 2005
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Re: Error code 78
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Fri, 21 October 2005 03:50
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Unplug your oxygen sensor, go for 4 short drives(so that any codes are recorded)it need not be far, just drive, stop, turn off, start, repeat.
If I'm right, there will be no new codes.
If there are no new codes, odds are your oxy sensor is screwed, which could give random high/low mixture readings.
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Location:
Sydney
Registered:
January 2003
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Re: Error code 78
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Fri, 21 October 2005 04:07
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Im pretty sure I found out what it is.... a yellow plug near the TVIS manifold not connected, must be air temp.
Sensor was there on my old TVIS manifold, but no sensor there on the new one !! I dont really want to change the TVIS manifolds back over. Ive put in a 3K resistor there in the meantime and it drives much better. I might just take the old sensor out and connect it up and leave it floating around the engine bay.
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Error code 78
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Fri, 21 October 2005 06:19
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78 is fuel pump ecu, so you definately don't have 78.
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Location:
Sydney
Registered:
January 2003
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Re: Error code 78
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Fri, 21 October 2005 06:46
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Connected the old air-temp sensor and just left it loose in the engine bay. Probably not the best place but works great for now!
Also timing was 0 BTDC, adjusted to 10 and feels much better.
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