Help! Car wont start OBD P0685.

[Paul77]

Good morning!

Patulong sana sa problem ng Kia Carnival 08. Car wont start. OBDII reading is P0685.
ECU/PCM power relay curcuit open. 1 1/2 months ba nka garahe ung van.

Thanks!

[12vdc]

Good morning!

Patulong sana sa problem ng Kia Carnival 08. Car wont start. OBDII reading is P0685.
ECU/PCM power relay curcuit open. 1 1/2 months ba nka garahe ung van.

Thanks!

Potential causes for this code to set are:
A defective PCM power relay
A blown fuse or fusible link Corroded or damaged wiring or wiring connectors (especially near the PCM relay)
Faulty ignition switch
Partially or totally disconnected electrical terminal at the ignition switch
Loose or corroded battery cable ends

Read more at: P685 ECM/PCM Power Relay Control Circuit Open
Copyright OBD-Codes.com

[travajante]

How's the batt?

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[baludoy]

Check the Main relay

when you look into the abyss, the abyss looks into you

[Paul77]

Potential causes for this code to set are:
A defective PCM power relay
A blown fuse or fusible link Corroded or damaged wiring or wiring connectors (especially near the PCM relay)
Faulty ignition switch
Partially or totally disconnected electrical terminal at the ignition switch
Loose or corroded battery cable ends

Read more at: P�685 ECM/PCM Power Relay Control Circuit Open
Copyright OBD-Codes.com

Main relay and fuse are ok.

Battery is 1month old. Cleaned the terminals already.

Ung engine nag ccrank pero d lng mag start. Parang mag sstart na ung crank nya

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How's the batt?

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Batt sir is new. Last oct lng nag palit.

[Paul77]

Check the Main relay

when you look into the abyss, the abyss looks into you

Main relay is ok. Abyss?

[travajante]

Check fuel pressure....if low or none, proceed to filter, then pump.

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[Paul77]

Check fuel pressure....if low or none, proceed to filter, then pump.

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Fuel pressure is ok. Na try din namin ibleed. Ayaw pa din

[travajante]

Fuel pressure is ok. Na try din namin ibleed. Ayaw pa din

What was the pressure the pump was giving?

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[Paul77]

What was the pressure the pump was giving?

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According to the mechanic of kia(casa) fuel pressure is ok pero wla silang device to measure it

[travajante]

According to the mechanic of kia(casa) fuel pressure is ok pero wla silang device to measure it

Reason I asked coz I've encountered failing pumps that still worked but gave pressures too low to fire engine up. Most injector rails have a Schrader valve for fuel gauge hook up. This helps eliminate suspects clearly. Some filter assemblies have a pressure regulator, too. If there is & it's faulty, the pressure reading would be low, too. Should fuel distribution check out, proceed to ground, harness & contact investigation. Cars in hibernation are a rodent fave. Check for chafed & split wires....this part I hate.[emoji852]

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[weisshorn]

Anong sasakyan?

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[Paul77]

Anong sasakyan?

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Kia carnival 08 sir

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Reason I asked coz I've encountered failing pumps that still worked but gave pressures too low to fire engine up. Most injector rails have a Schrader valve for fuel gauge hook up. This helps eliminate suspects clearly. Some filter assemblies have a pressure regulator, too. If there is & it's faulty, the pressure reading would be low, too. Should fuel distribution check out, proceed to ground, harness & contact investigation. Cars in hibernation are a rodent fave. Check for chafed & split wires....this part I hate.[emoji852]

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So d sya lalabas sa OBD na failing fuel pump? Or preasure is too low?

[travajante]

Kia carnival 08 sir

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So d sya lalabas sa OBD na failing fuel pump? Or preasure is too low?

Hit or miss, some failing pumps won't pop any code.

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[oj88]

Hit or miss, some failing pumps won't pop any code.

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The DTC points to a power supply issue that is either external or internal to the ECM/PCM. It's pretty far from being a fuel supply issue, isn't it?

[travajante]

The DTC points to a power supply issue that is either external or internal to the ECM/PCM. It's pretty far from being a fuel supply issue, isn't it?

Batt charge drops w/ all the crank attempts....& when it does, all sortsa random DTCs can pop. Have seen 1 case w/ a TCM code. Car cranked & started up fine but ran rough. Had the batt health checked, twas on its way out, but had enough juice left not to show signs. Cleared the code, same would re-pop. A day after, car's gauge needles would just sweep. Car failed to fire up. The only code extracted was for the same tranny fault. Re-cleared the code, swapped a new batt in.....car ran like new w/ no hiccups nor codes.
On huntdowns, a code reader is handy, but I would never downplay shared experience. A thorough elimination process, from easiest & least cost going up, will help pin this....There will be no harm checking fuel distribution to rule it out. Just my humble 2cents, good sir.[emoji4]

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[yapoy86]

Kia carnival 08 sir

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So d sya lalabas sa OBD na failing fuel pump? Or preasure is too low?

Na check mo na ba kung may kuryente sa mga injectors while cranking? Check mo din wires papunta sa ecm/pcm baka may kagat ng daga

[oj88]

Batt charge drops w/ all the crank attempts....& when it does, all sortsa random DTCs can pop. Have seen 1 case w/ a TCM code. Car cranked & started up fine but ran rough. Had the batt health checked, twas on its way out, but had enough juice left not to show signs. Cleared the code, same would re-pop. A day after, car's gauge needles would just sweep. Car failed to fire up. The only code extracted was for the same tranny fault. Re-cleared the code, swapped a new batt in.....car ran like new w/ no hiccups nor codes.
On huntdowns, a code reader is handy, but I would never downplay shared experience. A thorough elimination process, from easiest & least cost going up, will help pin this....There will be no harm checking fuel distribution to rule it out. Just my humble 2cents, good sir.[emoji4]

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I meant no offence. I just wanted to know your thought process.

Still, I think it's a "malayo sa bituka" sorta thing. Low or no fuel pressure will never cause an undervolt or power supply condition for the PCM. If any, it should be the reverse; ie. The PCM isn't receiving enough power so it's not working well enough to either command/engage the fuel pump, injectors or even the ignition system (petrol).

It's very likely that's the issue. The PCM is either unable or is actively preventing the engine from starting because of a power issue with the "brain". Not having fuel in the supply line (if that is indeed the case) is more likely a symptom, not the cause.

[travajante]

I meant no offence. I just wanted to know your thought process.

Still, I think it's a "malayo sa bituka" sorta thing. Low or no fuel pressure will never cause an undervolt or power supply condition for the PCM. If any, it should be the reverse; ie. The PCM isn't receiving enough power so it's not working well enough to either command/engage the fuel pump, injectors or even the ignition system (petrol).

It's very likely that's the issue. The PCM is either unable or is actively preventing the engine from starting because of a power issue with the "brain". Not having fuel in the supply line (if that is indeed the case) is more likely a symptom, not the cause.

None taken, sir.[emoji106] Car was repeatedly cranked. Voltage could've dropped & may have caused gremlins popping as it was sitting for a while...again, just to eliminate suspects.[emoji4]

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[barako ba ma]

Back to square one.
Check the basics.
Check fuses
Check fuel quality. (Might be stale fuel)
Check for spark at the plugs
Check exhaust restriction.


Don't get fixated on the DTC until you check the basics.

Try to recall what last thing was done before improperly "pickling" the car