Wires have no signal

Tiny
MUHAMMAD SAJID
  • MEMBER
  • 1993 TOYOTA COROLLA
  • 1.5L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
(4A-FE) How may I check that ECM is providing IAC valve signal without using any tools (as I have no scanning tool)? Checked IAC valve it is healthy and smooth. Also power (4.8 volts) is coming at one of three pins on IAC connector.
Thanks in advance for your help :).
Saturday, July 6th, 2019 AT 12:12 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,724 POSTS
Welcome to 2CarPros.

Here is everything I have on the IAC and testing. The attached pics correlate with the directions. Let me know if this helps. Note: A 1.5L wasn't an option, so since it is the 4A-FE engine, I think you meant 1.6L. Let me know if that is wrong.

___________________________________________

1995 Toyota Corolla Sedan 4-Door L4-96.8 1587cc 1.6L DOHC (4A-FE)
Idle Air Control (IAC) Valve Circuit
Vehicle Powertrain Management Computers and Control Systems Testing and Inspection Component Tests and General Diagnostics Idle Air Control (IAC) Valve Circuit
CIRCUIT DESCRIPTION

pic 1

The rotary solenoid type idle air control (IAC) valve is situated on the intake air chamber. Intake air bypassing the throttle valve is directed to the IAC valve through a passage. In this way the intake air volume bypassing the throttle valve is regulated, controlling the engine speed.

The ECM operates only the IAC valve to perform idle-up and provide feedback for the target idling speed. A vacuum switching valve (VSV) for idle-up control is also added (for air conditioning).

WIRING DIAGRAM

pic 2

CIRCUIT INSPECTION PROCEDURE

pic 3

pic 4

pic 5

pic 6

_______________________________________________

Also, here is a link that explains how to get trouble codes from this vehicle. You don't need a scanner for it.

https://www.2carpros.com/articles/toyota-trouble-code-definitions-and-code-gathering-method-1990-1995

Let me know if this helps or if you have other questions.

Take care,
Joe
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Saturday, July 6th, 2019 AT 8:45 PM
Tiny
MUHAMMAD SAJID
  • MEMBER
  • 1 POST
Thanks Mr. Joe.
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Sunday, July 7th, 2019 AT 1:50 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,536 POSTS
Please let us know what you find. We are interested to see what it is.
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Sunday, July 7th, 2019 AT 1:50 PM

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