Originally Posted by
jokersxf
Got the new RCU unit from a dealership. Swapped and no help. same black box no start
Turn the key to on and I hear the pump near the tank for a few seconds. And the dash peeps. Turn the key to start and nothing.
Gear indicator in the instrument panel has a black box but it won't let me take the key back unless the sla is in park.
What's my next step?
I disagree on using a DRBIII when the starter won't engage. if the starter won't engage AND you have those kinds of transmission/SLA error codes, I get the idea you have a 12 volt power problem. That is, you DON"T have 12 volts in one or more places you SHOULD have 12 volts. Now, if you can talk to the ECU, that tells me the ECU is powered up at least partially. But look at the diagrams in the service manual, many modules have multiple power feeds, each feed powers one or more areas of the module, but not always ALL areas in the module
It is hard to say what the next step is, as its becoming hard to follow what the exact symptoms are. Above, you describe a simple "no start, no crank" so lets forget this TCU crap and get the engine to start.
Basic test, when the car seems alive but it will NOT engage the starter:
Turn key to START, if starter wo'nt engage, relax key to ON.
Wait 30 seconds, do you hear the engine fan running fast, real fast?
If so, the engine control relay output from the RCM has failed, so your Fan module is alive, but your ECU is not alive. If the RCM is new, it's either the wrong one , bad, or a fuse on the RCM is blown.
If the engine fan is not running fast after 30 seconds, we have a "no crank" and that, in an automatic can have a lot of causes. But adding those SLA and transmission codes and symptoms, along with the issues driving it the last time, I insist this is a basic power problem.
As to the blank gear display, if the TCU is not powered up, you won't have a display. Now, they key is MECHANICALLY connected to the SLA, the key is not allowed to go be removed if the SLA is not in park. This is a simple cable connecction from the SLA to the ignition switch. There is a physical cable from the shift lever to the switch for this.
You cannot shift OUT of park unless your foot is on the brake pedal and the key is on, as the swtich on the brake pedal is there to prevent you from shifting from Park without the brakes applied, cuase to do so is stupid. This connection is a simple "power from key switch goes to brake switch, then to solenoid in the SLA" No computer is involved.