Corolla GTS Check Engine Light

Club4AG Regular
Posts: 10
Joined: Sat Sep 05, 2015 10:21 pm

Corolla GTS Check Engine Light

Postby CaliforniaHachiRoku » Tue Jan 02, 2018 5:15 pm

Hello Club4ag,
I'm trying to get my car smogged tomorrow, and I have a custom cluster in the car. This cluster lacked a check engine light, but when I tested the check engine light wire (green and white, pin 8 on ecu 18 pin connector), I was only getting about .24 volts (not enough to light up a light). Any advice would be greatly appreciated.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.

User avatar
Posts: 2585
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: Corolla GTS Check Engine Light

Postby jondee86 » Wed Jan 03, 2018 10:41 pm

JDM version looks to work like this... pretty sure the USDM will be similar...
1. 12V from GAUGE fuse to one side of Check Engine light.
2. 12V from other side of Check Engine light to pin W on 14-pin plug.
3. ECU turns Check Engine light ON by switching pin W to ground via pin E1 on 10-pin plug.

So with engine idling and no trouble codes latched, the Check Engine light will be OFF.
You should be able to measure 12V between W and E1. If not, check for 12V between W
and chassis ground. If you get 12V to chassis ground then maybe pin E1 does not have
a good ground connection. Check for continuity and low resistance between E1 and
chassis ground. Repair if necessary.

If you don't get 12V from W to chassis ground. check for blown GAUGE fuse or Check
Engine bulb. If fuse and bulb are good, check for wiring fault between GAUGE fuse and
pin W. I think it is normal for the Check Engine light to be ON when you turn the key to
the ON position (never actually took that much notice of mine :P).

And I can't say what would happen if there are fault codes latched by the ECU. My guess
is that the Check Engine light will either be ON full time or flashing. Either way you should
still be able to troubleshoot the wiring and power supply.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Return to “TECH: Corolla AE86”

Who is online

Users browsing this forum: No registered users and 22 guests