chaos2378

Good Morning,

I apologize in advance if this question has been answered before. I read quite a few threads, but all are about the green key light blinking or staying on. My problem is that the car cranks but does not start. There is no green light whatsoever, not when I insert the key, not when I crank, and not when I take the key out. Would it be wise to assume that the immobilizer unit is dead? Would replacing it with a new one off ebay, buying the SBB key programmer, and programming them myself be cheaper than having the dealer do it?

Thank you in advance!

Slumpertcivic

ezone

Never.
Test, don't guess.


No flashing green light at all = suspect lost power to the unit. Fuses? Relays?
Does the CEL also no longer light up when you turn the key on? (More clue)

chaos2378

I plugged in my OBD2 reader. It connected fine and showed no codes.

All the normal lights seem to work fine when the key is turned to the on position. The CEL lights up and stays on, which I believe is normal (I'm a Mazda guy and it stays on in those cars).



I began the troubleshooting by checking common causes to the "crank but no start" problem (before I realized the green key light didn't turn on). I checked fuses, changed both blue and brown relays under the glove box, checked rocker arm, and even unplugged battery overnight as a last resort. I'm stuck. Almost as maddening as figuring out the misfire on my RX-8. I will check fuses again to make sure. Does the orange light around the keyhole mean the unit is at least getting power though? Or is that not part of the immobilizer?

chaos2378

I plugged in my OBD2 reader. It connected fine and showed no codes.

All the normal lights seem to work fine when the key is turned to the on position. The CEL lights up and stays on, which I believe is normal (I'm a Mazda guy and it stays on in those cars).



I began the troubleshooting by checking common causes to the "crank but no start" problem (before I realized the green key light didn't turn on). I checked fuses, changed both blue and brown relays under the glove box, checked rocker arm, and even unplugged battery overnight as a last resort. I'm stuck. Almost as maddening as figuring out the misfire on my RX-8. I will check fuses again to make sure. Does the orange light around the keyhole mean the unit is at least getting power though? Or is that not part of the immobilizer?

ezone

That's a separate unit.



If you take off the column covers there are 2 green connectors on the 2 units by the keyhole. Immobilizer is the plug with 7 wires


Crappy incomplete diagram courtesy of goggle images





What you can't see here in the immobi CU:

Immobi CU wire #7 is constant power source from fuse #9 in engine compartment
wire #5 directly controls the green key symbol light

Between #2 and IMOCD lies the underdash fusebox

Between #1 and LG3 (logic ground) there are a couple of large harness connectors

ezone

The green key light should blink several times after you turn the ignition off.





If you have constant power to 7, switched power to 6, and good ground on 1 (I know I've seen issues with the ground in the past), and you can make the green light blink by supplying a ground to #5, then the immobi ring should be at fault.

Replacement unit must be programmed.