ECU codes

hotwheels · 05-19-2007, 01:01 AM

Can anyone please explain to me, in detail, how to get these so called 'ECU codes?'

Are these the same kind of codes you'd get when testing on an OBD2?
What if your check engine light is NOT on?

I just have a high idle and all other tests have failed, I think the problem is in the ECU. Can anyone please explain how to test an ecu to see if its working properly?

any help is greatly appreciated

seven_mgte · 05-19-2007, 03:10 PM

Ok, the codes for the mk1 (and all toyotas of this era) are similar to those in the OBDII systems but there aren't nearly as many of them, and they aren't as specific. Even if your engine light is not on, codes may be present.

to check your codes, open your engine lid and find the diagnostics connector. its mounted on the back firewall. with the ignition off. pop the cover open and use a bent paperclip or a piece of wire or some other conductor to jumper between the E1 and T terminals.

go inside the car and turn the ignition to the on position but do not start the car. The check engine light will blink according to the codes that are present.

If the light just continually blinks there are no codes, but it there are codes there will be gaps in the blinks.

there is a 1.5 second gap between the first and second digit, a 2.5 second gap between codes, and a 4.5 second gap at the end of the codes. they will repeat as long as the ignition is on.

The BGB outlines how to test an ecu, but it isn't as simple as plugging in a scanner like on newer cars. It requires a lot of testing of voltages and resistances using a multimeter.

hotwheels · 05-20-2007, 12:24 AM

Thanks a lot.

Where can i get a bgb? (Big Green Book?)

blazer9903 · 05-20-2007, 11:00 AM

I've got it. You can get them on Ebay for about $75-100 - but if you post your codes I'll look it up for you. They differ from 85-87 and 88-89 -

Solving them is a whole other story though. I've gotten a 12 (O2 sensor) and 21 (No RPM signal) on my '88 forever for no found cause. I know the 12 is the ECU itself b/c when swapped it disappears, 21 is always coding and as of yet, no idea why (in both cases all the diagnostics mentioned by seven_mgte check out OK). So I've lived with the constant check light

hotwheels · 05-20-2007, 10:22 PM

sweet.

I'll get it checked out soon, and post a reply, or else i'll pm you.

thanks

hotwheels · 05-22-2007, 12:28 AM

Ok, so I did what you guys said today. Here's what I'm getting.
blink twice, 2.5 sec gap, blink 6 times, 2.5 sec gap, blink 8 times, 4.5 sec gap, then starts all over.

So I'm guessing that the codes turn out to be 2, 6, and 8

Anyone know what these codes are?

THANKS A BUNCH!!

05-19-2007, 01:01 AM	#1 (permalink)
hotwheels elvis Join Date: Mar 2007 Posts: 33 Thanks: 3 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	ECU codes Can anyone please explain to me, in detail, how to get these so called 'ECU codes?' Are these the same kind of codes you'd get when testing on an OBD2? What if your check engine light is NOT on? I just have a high idle and all other tests have failed, I think the problem is in the ECU. Can anyone please explain how to test an ecu to see if its working properly? any help is greatly appreciated

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05-19-2007, 03:10 PM	#2 (permalink)
seven_mgte Cage Fighter Join Date: Aug 2005 Location: Coquitlam, BC.ca Posts: 327 Thanks: 0 Thanked 7 Times in 7 Posts My Google Map iTrader Rating: (0/0% )	Ok, the codes for the mk1 (and all toyotas of this era) are similar to those in the OBDII systems but there aren't nearly as many of them, and they aren't as specific. Even if your engine light is not on, codes may be present. to check your codes, open your engine lid and find the diagnostics connector. its mounted on the back firewall. with the ignition off. pop the cover open and use a bent paperclip or a piece of wire or some other conductor to jumper between the E1 and T terminals. go inside the car and turn the ignition to the on position but do not start the car. The check engine light will blink according to the codes that are present. If the light just continually blinks there are no codes, but it there are codes there will be gaps in the blinks. there is a 1.5 second gap between the first and second digit, a 2.5 second gap between codes, and a 4.5 second gap at the end of the codes. they will repeat as long as the ignition is on. The BGB outlines how to test an ecu, but it isn't as simple as plugging in a scanner like on newer cars. It requires a lot of testing of voltages and resistances using a multimeter.

05-20-2007, 12:24 AM	#3 (permalink)
hotwheels elvis Join Date: Mar 2007 Posts: 33 Thanks: 3 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Thanks a lot. Where can i get a bgb? (Big Green Book?)

05-20-2007, 11:00 AM	#4 (permalink)
blazer9903 No Skills Join Date: Apr 2007 Location: St. Louis, MO Posts: 14 Thanks: 0 Thanked 0 Times in 0 Posts My Google Map iTrader Rating: (0/0% )	I've got it. You can get them on Ebay for about $75-100 - but if you post your codes I'll look it up for you. They differ from 85-87 and 88-89 - Solving them is a whole other story though. I've gotten a 12 (O2 sensor) and 21 (No RPM signal) on my '88 forever for no found cause. I know the 12 is the ECU itself b/c when swapped it disappears, 21 is always coding and as of yet, no idea why (in both cases all the diagnostics mentioned by seven_mgte check out OK). So I've lived with the constant check light

05-20-2007, 10:22 PM	#5 (permalink)
hotwheels elvis Join Date: Mar 2007 Posts: 33 Thanks: 3 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	sweet. I'll get it checked out soon, and post a reply, or else i'll pm you. thanks

05-22-2007, 12:28 AM	#6 (permalink)
hotwheels elvis Join Date: Mar 2007 Posts: 33 Thanks: 3 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Ok, so I did what you guys said today. Here's what I'm getting. blink twice, 2.5 sec gap, blink 6 times, 2.5 sec gap, blink 8 times, 4.5 sec gap, then starts all over. So I'm guessing that the codes turn out to be 2, 6, and 8 Anyone know what these codes are? THANKS A BUNCH!!