1999 F150 Cranks but won’t start, only +1.1vdc to coil ckt of fuel pump relay and around +0.7vdc to relay coil ckt of PCM relay. Neither will switch @ this low coil voltage. I believe the truck may be trying to tell me something, but I can’t interpret the F150 language. The following sequence occurs every time I get in truck, shut the door, fasten seat belt and turn on ignition switch (not to “start”).



1.ABS light on 4 seconds then off

2.Series of 5 beeps five times sounds (but I know the air bag light is O.K.)

3.During the 5 beep series, all gauges activate plus low fuel (for 2-3 seconds), check engine, oil/temp light and fast blinking theft lights come on.

4.After about a minute the fast blinking theft light changes to a slow blink for 1 more minute, then off.

5.The gauges, the oil/temp light and the check engine light stay on until either the ignition switch is turned to start or to off. Either way, everything stays off until ignition off and then back on.

6.”Start” only “cranks” engine over and shuts down the gauges, check engine and oil/ temp. lights.

7. This same sequence repeats every time the ignition is turned on. If door is open, a chime beeps and door ajar light is on until the door is closed and a 6 beep seat belt warning with no light on sounds 1 time if the seat belt is not fastened.

8. Last night following the many times I had again checked fuses, relays, diodes, sensors, battery, alternator and voltages; I left the truck 8 or 9 hours with the check engine light, the oil/temperature light and the gauges on with the ignition switch on.

9. At 7AM this morning all were still on so I turned the switch to start and everything went off again. Turned ignition switch on again and same sequence.

10.Can anyone help?

 

PATS issue. If you have a spare key, try it. If it still does the same, the transducer in the steering column is suspect. If no spare key, it could be either.

Now - what does the odometer do? If it's all dashes, the PCM is not powering up, check relay and fuse.

 

Thank you for the advice. I do have both original chip keys and both do the same. I also have a no chip key in case I get locked out and I just tried the key with no chip and it results in the same exact sequence. Any suggestions on a next step?

 

Thanks again glc.
After reading the related thread I went back out and tried 12 times, one right after the other with no luck on starting. I then pulled the PCM relay, connected my VOM to the relay socket from ignition and the battery negative then placed VOM on windshield and turned on ignition switch (VOM read +0.07 VDC). Same procedure for Fuel Pump Relay and read +1.10 VDC. Neither was enough to activate either relay. Both relays have 12.9 VDC on the battery side of relay sockets and I thought about jumping both to see if truck would start but I didn't want to damage any of the control modules.

 

odometer is not on at all (totall black) and same for air bag warning light which did light on initial "prove out" before this no start started yesterday.

 

You don't have a PATS problem, it's a "secondary" symptom. You may have a power distribution problem that is preventing, at a minimum, the PCM from powering up. Separately, you may have an odometer blackout issue.

FWIW, when you say "+1.1vdc to coil ckt of fuel pump relay and around +0.7vdc to relay coil ckt of PCM relay." you MUST give the pin # of your test point as well as the test condition, otherwise there's too much vagueness. Ignore the fuel pump relay until you solve the primary issue.

Verify fuse F30 is HOT IN START/RUN and is passing power,

Then try swapping the PCM Power Relay with another non-critical relay and test. Mark the relays first!

 

Thank you so much for your advice.projectSHO89. My no start problem was F30. I had pulled all fuses and checked with VOM only for continuity, but F30 spades were not making contact with the 12 VDC fuse box socket from run/start ignition switch power. I scraped off the fuse spades and reinserted the fuse.Bingo, everything came uu except the odometer. I pulled the instrument panel and re-soldered pins on pc board @ ribbon connector for odometer and when I re-installed instrument panel the odometer came on too. I really do appreciate your help.

 

Good deal. Glad it's back on the road.

Let this result serve as a reminder that troubleshooting must be done from a "top down" perspective. One has to verify prerequisite conditions before jumping to conclusions regarding what I termed "secondary" symptoms. I had the good fortune to attend a specialized electronics troubleshooting course about 40 years ago while I was stationed in Germany where the two "seasoned" instructors spent large amounts of time focusing on such prerequisites such as grounding and power feeds to circuits. That lesson stuck with me over the years. Passing it on...