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wont start, need help with codes P0603 & P1660

4K views 12 replies 4 participants last post by  John_G 
#1 ·
Hey guys, my truck slowly died the other day went from normal to lack of power to no power what so ever and eventually dies on the side of the road, this happened over a 400mile trip.

The truck now wont start and has two codes;

(P0603) = CONTINUOUS DTC P0603 INDICATES PCM HAS EXPERIENCED A POWER INTERRUPT IN KAM CIRCUIT. [KAM == Keep Alive Memory]

(P1660 OR P1661) = INDICATES THAT OUTPUT CIRCUIT CHECK IS HIGH OR LOW.POSSIBLE CAUSES ARE:HIGH SYSTEM
VOLTAGE, VREF CIRCUIT FAULT;

I don't understand what they mean or what where to do next. :eek:wned
 
#2 ·
Did you check ALL the fuses? It's relatively common for the fuel heater element to short out which causes the PCM fuse to fail. But, you get codes so that's good.

Do the WTS and Check Engine lights come on with the key? If so, that's VERY good.

Next, when you crank it, does the tach indicate RPM? If not, you may have simply a bad cam sensor.

P1660/1 indicates a short in an output circuit from the PCM, IPR valve and EBP solenoid are the two main ones and if one is dead shorted, that would keep it from starting.
 
#4 ·
My 97 is popping the same code. I just had a Sniper chip, new valve cover gaskets, wiring harnesses under the valve covers, and a glow plug relay. It drove fine and now I have codes P0603, P1391 & P1393. Now my truck for start. It turns over good but I don't get a "Wait to Start" light and the glow plug relay doesn't click. I have checked all the fuses (ohms test) all are okay. Could it be the new Sniper chip?
Thanks,
Matt
 
#5 ·
A friend is comoing over today with a better scanner.. The ses light is not on but there are codes stored, we are going to erase those codes and start new.

From the research i done, code P0306 is not very important, power loss from batteries, i did had bad batteries two months ago but never saw any ses light then now now.

The next code is somewhat tricky as it could be a number of things, once i get to run more test later today i'll be able to zoom in into the actual problem(s)

The wait to start light is working fine, as is the ses light. Tach does move when cranking. I dont think its got to do with wiring, the truck slowly died in the course of 400 miles.
 
#6 ·
puzzled at a higher degree

I just ran a few test on it with a genesys system scanner with software v2.0

Injector Control pressure: peaked at 2600
Injector Press Reg duty Cycle %: when keywas at the on position it read 15% and raised to 39-44 when engine was cranking..

so, do i have a high oil pressure leak and also starving for fuel??

PS. i disconnected the batteries and removed the chip, the only code in the pcm was the 0306 related to power failure, once deleted from the pcm no code ever came up after cranking the truck for 5-6 times. So, i have no codes now?!? :bang:
 
#7 ·
the truck slowly died in the course of 400 miles.
Injector Control pressure: peaked at 2600
Injector Press Reg duty Cycle %: when keywas at the on position it read 15% and raised to 39-44 when engine was cranking..

so, do i have a high oil pressure leak and also starving for fuel??
Fuel, not oil. Oil pressure will rise like that when you are cranking, especially if there's no fuel.

Check to see if you have fuel in the bowl.
 
#11 ·
Which means the injectors aren't firing.

Now you've got some work ahead of you. You say there is fuel, you've verified that oil pressure is there, the tach moves so that means the CPS is working.

What's odd is that you mentioned that it slowly lost power and died over the course of a 400 mile trip. Most electrial issues are instant shutdown, where slow loss of power is usually a fueling issue.

The only electrical problem that I can think of that might cause a slowdown over time is a dying alternator. I've had issues last summer with my last alternator. It was slowly dropping voltage and very slowly killing the batteries. My truck was losing power, and I was trying to figure out for the life of me what was happening. I started tracking the alternator voltage and noticed that it wasn't powering like it should. I replaced the alternator, charged the batteries, and it ran like new again. It was an odd problem, but it happened.

Some things you can test.
1) Check your system voltage. Injectors require a minimum of 10.5 volts to fire. Anything less, and you won't get a drop out of them.
2) If voltage isn't the problem, hook up a fuel pressure gauge to the fuel rail and check fuel pressure to see what's happening.
3) If fuel pressure isn't the issue, try forcing the PCM to set codes. How long are you cranking? 5 seconds at a time? 10 seconds at a time? If you haven't done any extended cranking yet, try turning it over for about 15 seconds. In some situations, certain trouble codes won't be triggered unless a certain amount of time has passed to see the fault. For example, it takes 7 seconds of a low or high oil pressure condition before the PCM triggers a P1211 code. There are several codes that have similar time limits associated with them.
 
#12 ·
there is fuel there alright, i didnt screw the fuel cap right yesterday and when i tried to start teh engine again a stream of fuel came out from it.

i was told today that it could be the pickup screen(s) in the tank that is/are probably clogged. the fuel pump seems to be a bit quieter than normal, but if that's the case how im in getting fuel to the bowl?

whats the max amount of time i can crank the starter without causing damage?
 
#13 · (Edited)
I agree with your comments about fuel in the bowl, if you have fuel spraying from the bowl, the pickup is not clogged to the point that it should not run.

There is no max amount of time for cranking, you do NOT want the starter to get too HOT. Generally, for every 30 seconds of cranking, you wiat 2-5 minutes.

So, you have NO FUEL, why?

Check the IDM and injector wiring. The scanner, if decent, will be able to run the "injector buzz test", if that passes, you DO NOT have an electrical problem to the injectors.

You are getting good ICP during cranking and good IPR valve control, so it should run.

It sure sounds like a fuel problem, not enough pressure or something. They really do need fuel pressure of about 20+ PSI to start.
 
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