Stalled then no crank

2005 FORD TAURUS
234,000 MILES • 3.0L • V6 • 2WD • AUTOMATIC
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JMAN74
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I got a check charging system message a few days ago then it went away. I figured the alternator would be going soon. I started it up today, fired right up, started out the drive and it stalled as I pressed the accelerator. Tried to restart but nothing. Silence. A single click from under the dash and silence. I had been having issues with the TRS in the past so I changed it. Same result. I can roll the starter by jumping the relay. When I test the solenoid for juice when turning the key I get nothing. I also never get juice to the second pin on starter relay when key is turned. Something is not allowing the signal to pass to the starter relay and additionally not allowing spark at coil pack. Any ideas on where to check? I have tried all I can on this forum. I am using a battery jump box 700A to assist. Bright lights no dim when key turned, radio intermittent when key is in on position.
Oct 26, 2018 at 11:23 AM
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ASEMASTER6371
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Good evening.

I would start by checking the fuses with a test light. Check for power on both sides.

I attached a wire diagram for you to view.

The relay should have battery power to the relay and another power when you turn the key to start.

Check for those voltages.

Also, check the battery. you should have 12,6 volts at the battery. If it is lower, charge it to 12.6 volts.

Roy
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Oct 26, 2018 at 4:11 PM
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JMAN74
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Thanks for the checks and wire map Roy. It started raining here and so I will update tomorrow after performing your suggestions. I also plan on cleaning all grounds and connections in the starting system. That may also reveal the snake. :)
Regards
Oct 26, 2018 at 6:27 PM
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ASEMASTER6371
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Sounds like a plan.

Roy
Oct 27, 2018 at 6:10 PM
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JMAN74
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Hello again,
Okay - I have no voltmeter so all tests were done with a test light.
1) Battery charged to 12.6 volts (Checked this through the "Engineering Test Mode" on digital cluster display).
2) Disconnected and cleaned all contact points and checked for both current and ground.
3) Checked relay points for current: PIN30(constant), PIN86 (On when key is in start).
4) PIN 85 shows on diagram as NEG from PCM which I never get anything from.

Without a meter which I am trying to get a hold of I do not know what or where to check.
Oct 30, 2018 at 12:50 PM
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ASEMASTER6371
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Okay, how did you check for current and ground with a test light? A test light cannot test current.

Try this. Use a jumper wire and jump 30 to 87. See if the starter cranks over the engine.

Roy

Oct 30, 2018 at 12:55 PM
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JMAN74
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Sorry I only tested for voltage to light the bulb at 30 with clip on neg terminal. Tested 87 with clip on positive. I used the jump wire and the starter will turn all day. Nothing else.
I should note if I have not already that I also replaced the TRS sensor with a new one. While in test mode the displays shows "$MIS" when i navigate to the PRND input
Oct 30, 2018 at 1:04 PM
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ASEMASTER6371
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Okay, then the load side of the relay is good.

If you have power to the control side in the start position as you stated, the PCM is not grounding the relay to energize the load side. The only signal it looks at is the range sensor input. It needs to see park or neutral.

Can you verify park or neutral on your scan tool?

Roy
Oct 30, 2018 at 1:12 PM
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JMAN74
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Ok thats exactly what I thought from the diagram. I wont have the OBD until later today and Ill see if I find it there along with any pertinent TC's. All I have electronically to check now is the cars Engineering Test Mode on the display which shows "$MIS" when I navigate to the PRND status.
Is the TN/RED from TRS outbound charged if the shift lever is in P/N?
Oct 30, 2018 at 1:21 PM
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ASEMASTER6371
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In park or neutral, that wire should have power. It goes to the relay.

Roy
Oct 30, 2018 at 1:27 PM
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JMAN74
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Okay, I will check that along with the BRN/PK input from ignition (on start) while I wait for scan tool and meter.
Oct 30, 2018 at 1:29 PM
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ASEMASTER6371
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Sounds like a plan.

Keep me updated.

Roy
Oct 30, 2018 at 1:34 PM
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JMAN74
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Hey Roy,

Okay, so I have not been able to get my hands on the scan tool. I did however get the meter. Here is what I checked and results.
At starter relay sockets (With Key in "run" position)
PIN 30 - 12.8 V
PIN 87 - 0
PIN 86 - 9.7 V
PIN 85 - 9.7 V
I am assuming that because 85 gets its ground from PCM that I have an issue from PCM and because 85 is + volts I am getting the proper signal from the TRS correctly?

Thanks!
Nov 1, 2018 at 1:05 PM
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ASEMASTER6371
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86 needs a signal when the key is in the start position.

Did you check that with the key in the start position?

Roy
Nov 1, 2018 at 1:14 PM
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JMAN74
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The readings are almost identical on 85 and 86 in all key positions.
Key off - 0.3
Key on - 8.97
Key in start - 8.97

Once the ignition is released from start position the readings drop to 0.3 again on both pins. If turned to start position without turning the key off then the readings go from
ON - 0.3
START - 8.97
ON - 0.3
etc
If I return to the off position then each time I go from off to start it begins at 8.97. Am I making sense? lol
Nov 1, 2018 at 1:32 PM
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ASEMASTER6371
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The fact is there is not enough voltage to close the control side of the relay.

It needs to be the same voltage as 30 in the start position. The issue is no voltage to that pin. it comes from the range sensor when the transmission is in park or neutral.

Roy
Nov 1, 2018 at 1:45 PM
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JMAN74
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Ah ,well let me tell you this then.
I noticed when I was hold my test light on PIN 85 the radio turns on when key is in "on" position. When I remove it it goes off.
Then while testing the harness at TRS in/out same thing.
Do not know if it helps identify or not but it happened. lol
Should I unwrap the wiring in that area to see where I may be losing voltage?

So you are saying the PCM will not send that ground signal until 86/85 gets matching volts to 30?
Nov 1, 2018 at 1:52 PM
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ASEMASTER6371
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Look at the diagram and check the brown/pink wire for voltage.

Roy
Nov 1, 2018 at 1:57 PM
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JMAN74
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Okay, the brown/pink wire has 12 volts at the TRS, so does the tan/red at the TRS when the key is in start.
The relay is only getting the 9 volts.
Nov 1, 2018 at 3:40 PM
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ASEMASTER6371
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Okay, good.

Then you have a wiring harness issue between the range sensor and the relay. You will need to check the harness for damage.

Roy
Nov 1, 2018 at 3:52 PM
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JMAN74
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Okay. A visual on the harness looks good. All those wires do go into what looks like a big rectangle shape junction box. Should I only trace the tan/red wire all the way to the relay looking for issues?
Nov 1, 2018 at 4:04 PM
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ASEMASTER6371
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Yes, that is the wire were are concerned about.

Roy
Nov 1, 2018 at 4:08 PM
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JMAN74
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Okay. Thanks Roy! I will update you tomorrow! Time for beer!
Nov 1, 2018 at 4:16 PM
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ASEMASTER6371
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Sounds like a plan.

Keep us updated.

Roy
Nov 1, 2018 at 4:17 PM
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JMAN74
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Hey Roy - apologize for the gap in reporting back. A buddy of mine thought the guys at his shop could find the issue quickly. Not only was it not quick, they also have not found the issue other than to say I'm getting back feed to pin 85 on the relay.
Nov 25, 2018 at 9:36 AM
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ASEMASTER6371
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It sounds like your buddies shop has no idea what they are doing.

Pin 85 gets its power from the park neutral switch when in the start position. That is what is supposed to happen. 86 is the ground side of the relay. The PCM grounds the relay so the solenoid will get power.

You need a real shop with a real tech that can do proper diagnostic checks. This is a simple check by a tech.

Roy
Nov 25, 2018 at 9:44 AM
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JMAN74
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Thanks and I agree. So I am back to working on it myself. I love the challenge and learning so I am going to continue to trouble shoot it, hopefully with your help. So I will let you know where I am in the hunt.
12+ Volts at PIN 30 always
0 Volts at PIN 87
In off position PINs 86/85 have about 1/2 a volt
In run position PINs 86/85 have 8+ volts

So is the pink wire to PIN 86 the one I need to trace since it seems I'm getting no ground there?
Nov 25, 2018 at 9:59 AM
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ASEMASTER6371
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85 should have power in the start position. 86 goes to the pcm and the pcm grounds that wire to energize the relay. 87 will be hot when the relay is energized.

Roy
Nov 25, 2018 at 10:09 AM
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JMAN74
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Okay, so based on that we can conclude that because I have 8+ volts at 85 in start the TN/RD from TRS is okay, but the PNK from PCM to 86 may have issue or the PCM itself?
Nov 25, 2018 at 10:14 AM
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ASEMASTER6371
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No, you should have battery voltage to 85 not 8 volts. Check the incoming wire from the fuse block to the trs for battery voltage in the start position.

Roy
Nov 25, 2018 at 10:16 AM
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JMAN74
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Okay, I have 12+ on the BN/PK from fuse block at start. TN/RD at the TRS does not go higher than 8+ volts.
Nov 25, 2018 at 10:27 AM
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JMAN74
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Not sure if this tells you anything or not but I noticed in the diagram that theres a jumper from 85 to the audio system fuse in the BJB. The radio does not work when key is in the on position while the 5amp fuse is in place. If I remove that fuse the radio works. Could be a rabbit hole but just wanted to point out everything I can in this system.
Nov 25, 2018 at 10:32 AM
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ASEMASTER6371
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You could try unplugging the radio and see if it makes a difference but 8 volts is not enough. The TRS may be the issue.

Roy
Nov 25, 2018 at 10:38 AM
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JMAN74
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I also replaced the TRS with a new one. Same readings.
Nov 25, 2018 at 10:40 AM
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JMAN74
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Okay, I will go unhook the radio.
Nov 25, 2018 at 10:40 AM
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ASEMASTER6371
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Sounds like a plan.
Nov 25, 2018 at 10:41 AM
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JMAN74
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Okay, unplugged the radio harness. Same readings.
Nov 25, 2018 at 10:53 AM
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JMAN74
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Seems something is pulling the 4 volts off of the TN/RD since the infeed is giving 12+. SMH.
Nov 25, 2018 at 10:55 AM
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ASEMASTER6371
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I figured that. Verify the input to the TRS is the same reading as at the fuse block.

Roy
Nov 25, 2018 at 11:00 AM
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JMAN74
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Okay checked, we have matching 12+ volts at SJB and TRS input (PIN10/ BN/PK) on TRS.
Nov 25, 2018 at 11:10 AM
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ASEMASTER6371
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Okay. Either it is out of adjustment or the new switch is no good.
Nov 25, 2018 at 11:17 AM