Code po 1389

Tiny
HOPERAY28@GMAIL.COM
  • MEMBER
  • 1998 DODGE RAM
  • 5.2L
  • V8
  • 4WD
  • AUTOMATIC
  • 198,000 MILES
Started with a bad fuel relay board, so I ran the relay wires to the fuse with extended wiring. Then I burned up pump, change fuel pump, then lost spark. Put in new crank sensor, cam sensor, distributor cap, plugs and wires relays, fuses redid grounds. Changed ECM, changed ASD inspected the wiring harness. I have lots of fuel pressure from pump to fuel rail. Also changed coil to new with diagnostic code po 1389 comes up. What is the fix to get this truck running? Help!
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Tuesday, November 5th, 2019 AT 4:13 PM

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Tiny
SCGRANTURISMO
  • EXPERT
Hello,

This Direct Trouble Code[DTC] is for No ASD Relay Output Voltage at PCM. In the diagrams down below I have included the diagnostic troubleshooting flowchart for DTC P1389 in the diagrams down below. It will require the use of a code reader and a Digital Multi-meter [DMM], so here is a link below explaining how to use one, if needed:

https://www.2carpros.com/articles/how-to-use-a-voltmeter
,
Please go through these guides and get back to us with how everything turns out.

Thanks,
Alex
2CarPros
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Tuesday, November 5th, 2019 AT 5:27 PM
Tiny
CARADIODOC
  • EXPERT
P1389 - No ASD Relay Output Voltage At PCM

I suspect this fault code set when you had the ASD relay out of its socket at a time you turned on the ignition switch. When you turn the ignition switch on, the Engine Computer initially turns the ASD relay on for one second to run the fuel pump to be sure fuel pressure is up for starting in case it bled down over days or weeks. That alone can provide misleading clues because since fuel pressure looks okay, we tend to concentrate on the ignition system.

The ASD relay sends current to the ignition coil(s), injectors, alternator field, oxygen sensor heaters, and the fuel pump or pump relay. There's one more place that sees 12 volts from the ASD relay. That is one of the terminals for the Engine Computer. This is the circuit involved in setting fault code 1389. The computer thinks it grounded the coil of the ASD relay to turn it on, then it expects to see 12 volts on that terminal for one second. If you had the relay out, that won't happen, so the code is set.

Since you've been jumping around, lets start with the ASD relay. We know it's turning on for one second because you have fuel pressure. That tells us the relay is okay and the computer has control over it. Next, what is important is if that relay turns on again during engine rotation, (cranking or running). The easiest way to determine this is to connect a test light that you can see from inside the truck. Connect the probe to the dark green / orange wire at the ignition coil, any injector, or either smaller terminal on the back of the alternator. You'll see the test light turn on full brightness for one second when you turn on the ignition switch. Does it turn on steady when you crank the engine?

If the test light does not turn on during cranking, the signal is missing from the crankshaft position sensor or the camshaft position sensor. Very often diagnostic fault codes don't set for them just from cranking the engine. They need more time to be detected, as in when a stalled engine is coasting to a stop. Therefore, don't assume either sensor is working just because there's no related fault code. You'll need a scanner to see the status of those two signals. Chrysler's DRB3 lists them with a "No" or "Present" during cranking. Other scanners should have some similar method of showing if those signals are showing up.

The sensors account for about 95 percent of crank / no-start problems. If the ASD relay is turning on during cranking, the two sensors are working, then we have strictly a fuel supply problem or an ignition system problem.

Let me know what you find up to this point.
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Tuesday, November 5th, 2019 AT 6:11 PM

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