code 12

hornet7288

Member
Oct 18, 2005
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I am getting a code 12. I recently repaired a massive leak in the intake manifold gasket. It runs so much better now. I have also replaced all plugs, wires and cap/rotor. What could be giving me this code?
 

CRE

7M-GE + MAFT Pro + T = :D
Oct 24, 2005
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Denver, CO
Toyota Service and Repair Manual said:
Code 12 - RPM Signal


Diagnosis

* No "NE" or "G" signal to ECU within 2 seconds after engine has been cranked.

Trouble Area

* Distributor, or CPS, circuit
* Distributor or CPS
* Starter signal circuit
* ECU

Well, have you actually checked anything specified for that code?

I'd start with making sure the harness running to the distributor is securely connected and that the wires are in good shape. It seems that problems at the distributor are the most common cause.

Good luck! :D
 

hornet7288

Member
Oct 18, 2005
260
0
16
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Savannah, GA
CRE;1466336 said:
Well, have you actually checked anything specified for that code?

I'd start with making sure the harness running to the distributor is securely connected and that the wires are in good shape. It seems that problems at the distributor are the most common cause.

Good luck! :D

I need to start checking these things. THe car seems great except when I run it when it's cold. It seems to really bog at certain rpm's, but otherwise it seems to do fine once it's warmed up.
 

cuel

Supramania Contributor
Jan 8, 2007
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Baytown, Texas
What year?
I found a tech. serv. bulletin for cold hard start/driveability on 89 and 90 models. If the complaint was both cold start and driveability, tech was instructed to install an updated ecu. Have to have the 22 deg. Celsius c.s.i ti.me switch, as the improved cold start injector logic was programmed to work with that one only. This was after making sure all mechanical, fuel, and electrical/electronic systems were operating within specifications

Reference: engine number: 024 date 08-31-90.

For cold start ONLY issues, toyota has an improved c.s.i. time switch that changes from 22C(72F) to 45C(113F). they are marked on the hex with either a 22 or 45.

EDIT: this is only for the cold hard start/driveability issue, not the code 12.