Hi All! I'm new here. Great sight BTY!. I need help. I have a 99 GT. Last February I did a Mark 8 swap. SCT email tune-PATS disabled. Everything ran good. Every once and a while, it would miss and idle low. Always came out if it. Last year, Went to start and wouldn't turn over. Tried it the next day and started right up!!??!? Never happened again. I put a T56 trans in last week and now it wont turn over again. Starter not engaging. Has a PATS code 16. Did the cluster diagnose and has a 262 code. Odometer shows mileage. Tried both keys and fobs. Unhooked battery, checked Volts (11.89). Waited 30 mins and did a load test(11.02). Checked fuses (all good) and cleaned all grounds. Checked grounds going in to the ECM. 25,3,51,77,103,. All were good except 25. Also, The ground under the battery tray, one is BK/WT and the other is BK/YL. The Bk/YL showed open as well. I traced it to under the drivers fender and goes in under the dash main harness. I don't know where those grounds connect to.(Pin 25 on ECM and Bk/YL wire inder dash) Can anyone help?? I'm sure I'm just over looking something. Any help is much appreciated.
Electrical Issue, 99 Gt Wont Turn Over, Pats Code 16,262
- Thread starter Bford
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wmburns
SN Certified Technician
Please confirm that the problem is a crank with no start or a "no crank".
The open ground on PCM pin #25 is important as likely this means the main PCM/CCRM ground has become disconnected. Please check out this recent thread that describes the EXACT ground in question. This ground harness goes around the battery on then onto the radiator core support. There's a round connector that sometimes gets disconnected during a battery swap.
https://www.stangnet.com/mustang-forums/threads/engine-still-cranks-with-no-start-after-swap.896214/
The open ground on PCM pin #25 is important as likely this means the main PCM/CCRM ground has become disconnected. Please check out this recent thread that describes the EXACT ground in question. This ground harness goes around the battery on then onto the radiator core support. There's a round connector that sometimes gets disconnected during a battery swap.
https://www.stangnet.com/mustang-forums/threads/engine-still-cranks-with-no-start-after-swap.896214/
This is a "no crank". The engine will not turn over. I cleaned and checked the grounds on the radiator core. Found the ground under the battery in the round connector and checked it all the way to the drivers side inner fender. BK with YL stripe. It goes into a connector on the firewall. I separated the connector and checked the wires again. The ground is good from the radiator core to the firewall connector. From there I checked the connector from inside the firewall back to the core support and no connection. I hope this makes sense. I also found a ground on the passenger side of the console, about knee high. I don't know if this is the radio ground. This one shows .03 ohms of resistance. There's also a single ground by the ECM that was not attached. Looks like it had never been attached. I was hoping this was the problem. I installed it and still no luck.
wmburns
SN Certified Technician
So what have you done to trouble shoot the neutral safety switch (NSS)? Seems strange that the problem began after a transmission install.
Were there any problems during the transmission install? All bolts installed on the starter?
Confirm the motor grounding strap from the left hand motor mount to the frame rail. This should be near the oil filter. IF this grounding strap is missing the starter motor may not be able to draw enough current.
Are you able to turn the motor over by hand using a wrench on the front crank damper?
If this were my car the first test would be to jump the starter solenoid at the starter solenoid to "prove" the starter itself works. Be certain that the transmission is in neutral before performing this test.
Next test is separate the single white wire with a pink stripe (WH/PK) near the battery. This the starter solenoid circuit. Jumping +12 volts directly towards the starter should engage the starter and crank the motor. IF the starter engages, this "proves" the starter pilot duty relay and stater solenoid works.
IF the starter does NOT engage, the problem is in the starter pilot circuit (fuse, relay, ground).
IF the start does engage, the problem is likely in the clutch NSS or ignition switch. Test for +12 volts in the RD/LB wire (other side of the WH/PK wire with the key in start and the clutch depressed. IF no power, that confirms there's a problem in the NSS circuit. Repeat the test at the clutch NSS switch.
OBTW, the PATS code has nothing to do with the no-crank problem. The car is failing PATS each time but because PATS is disabled inside the PCM, the motor starts anyway.
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You are the MAN wmburns!!! I bypassed the NSS and it fired right up!! I hooked it back up just to verify and no crank. I bypassed it again and fired up. I would have never though of that! Iv'e been racking my brains (what I have left) for almost 3 weeks now. Thank you.
