I have Mazda Tribute FWD V6 2001 model, about 70,000 miles. The starter motor does not run when an ignition key is turned to the engine start position few minutes later after stopping the engine.

What I checked and confirmed are;
* All lamps on an instrument panel turned on as usual
* No MIL lamp has been on
* No start relay in a junction box was working (no sound or vibration when becomes on)
* All fuses are OK
* I checked the start relay alone and confirmed it is OK
* I checked a diode that connected to the cold side of the start relay and confirmed it is OK
* So, I made a short circuit from the cold side of the start relay’s coil to the ground, and then turned the key to start the engine. The start motor runs! By this test, I conformed that all circuit to run the start motor (including the gear lever switch and an igniting switch) is OK
* I diagnosed the PCM using EMLScan tester and diagnosis software because the cold side of the start relay’s coil is connected to the PCM. But no DTC was reported.
*The scanner and software may not read all DTC as they are for basic analysis, so DTCs for transmission and other essential components to start the engine are unknown at this moment.

I doubt the Transmission Range sensor because it transmits a signal to the PCM to allow starting the engine when the transmission is only in Park or Neutral position. However I am not sure because I can not read P07XX trouble codes.

Please advise what is the most doubtable component(s) to make such problem from your experience. If I have a better performance test that can read all Mazda DTC, I could better job but…

Thank you for your help

 

Had this problem with my 1990 Miata. Turned out to be a corroded treminal at the starter terminal!

 

Hi dblotz,

Thank you for your input. I think the starter motor circuit is OK because 1) the start relay does not work when the key is turned to the start position - this means that the start motor activation circuit is open, 2) the start motor works when the cold side of the start relay's coil is directly grounded skipping a ECU (the cold side of the start relay's coil is connected to the ECU as per diagram). This is why I doubt something inside the ECU prohibits the start relay circuit completely closed (making the relay working).

Thanks again,

 

check for tight connections on both ends. there may be corrosion or such on the connector. a good steel brush or a scotch brite pad should do it also make sure connections are tite.

 

OP, why do you not just install a new Starter?

-Sheldon.

 

Thanks Bobs,

The problem was at the connection of wiring from a battery junction box to an ECM. Under the battery junction box located front right next to a battery, there is a main connector which connect electrical parts in the box to their various destinations. A connector pin from a starter circuit's diode was corroded. So, the current to activate the starter relay did not get through.

I became very aware that such small bad contact in the starter motor circuit make serious problem in the car operation.