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what is code PO603

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Old Dec 7, 2010 | 07:01 PM
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what is code PO603

As I posted in my last thread my torque convertor started jumping in and out of lock up in od my buddy had my truck scanned 2000 f350 and the only code it showed was a PO603 what does this code mean?
 
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Old Dec 7, 2010 | 07:15 PM
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That code will set anytime the PCM looses power, as when you lift the battery cables to work on your truck. It will also set with a chip installed. Nothing to worry about.
 
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Old Dec 7, 2010 | 07:56 PM
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I've checked all the wireing, had it hooked to a scanner and looked at all the sensors, is there anything else to check before I take it to the tranny shop and have them look at it?
 
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Old Dec 7, 2010 | 08:05 PM
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Not all scanners can pull codes from our trucks. Was the CEL on or the OD light flashing? What type of scanner was used? The cheap, free scans don't work for us.
 
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Old Dec 7, 2010 | 08:59 PM
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no the SES light has only ever came on when i ran over 35psi of boost for a short period of time. and no OD light flashing. The scanner was a high dollar snap on i know it will read our trucks i used to work for the guy that scanned it. I have used the scanner to diagnose many trucks like ours and it worked fine. Does anyone have a wireing diagram of the harness that goes to the tranny? Im trying to check everything i can before it goes to the tranny shop and they find something that is not under warranty with the tranny to charge me for.
 
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Old Dec 7, 2010 | 09:12 PM
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This is for a 1999, but should be the same for 2000.

Very bottom & center of page is the tranny connector.
 
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Old Dec 7, 2010 | 09:20 PM
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how would i go about testing the shift solenoids and the torque convertor clutch solenoid to see if they are working or not? what voltage or ohm reading should the purple/yellow wire have if im looking at the wiring diagram right that is the one for the torque convertor lock up clutch
 
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Old Dec 8, 2010 | 07:33 AM
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Well I think I've checked all I can check the tranny is still under warranty so monday it is going to the shop that rebuilt it and they can fix it. I've only got about 35,000 mile on it.
 
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Old Dec 8, 2010 | 09:58 AM
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I'm not good at searches here but there was a thread some time ago about a non-working tail light causing the torque converter to not lock.
Yes, I meant what I said. Seems so crazy but the OP had stated this issue from a manual.
Also some theory that LED lights may cause this too.
 
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Old Dec 8, 2010 | 05:20 PM
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All of my lights work. My LED lights are all aftermarket I have ten LED cab lights and 6 lights LEDs down each side of my truck.
 
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Old Dec 8, 2010 | 06:11 PM
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LED lights often do not have enough resistance. you will have to add a resistor inline for the computer to see that the light is actualy working.( We are talking about the third break light here )
 
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Old Dec 8, 2010 | 06:40 PM
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The third break light is still stock.
 
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