Question about 1993 Ford Ranger SuperCab

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DTC 542 I have a code 542 Fuel Pump Circut open, PCM to Motor. I have not been able to find a flow chart for this code. Does any body know where to find one.

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  • slaeger Dec 28, 2008

    It does start and the engine is a 4.0L. 1993 Ranger 4x4. I also had a fuel pressure regulator problem that filled the cylinders with fuel and the upper intake. I can go to the local Ford Service Dept. and get a copy of the flow chart. I just thought there may be a chart avaliable on line.

  • slaeger Dec 28, 2008

    Most service departments will make you a copy of the particular section if you know what to ask for. I am a retired ASE Master Technician And i worked for GM for about 20 years. I used to help the local independent guys whenever they needed service manuels and advice. I have not worked on many fords and i thought this would be a good place to find some info.

  • yadayada
    yadayada May 11, 2010

    Mine wouldn't.

  • yadayada
    yadayada May 11, 2010

    Ford will just hand out free tech manuals?

  • Rick Byrd
    Rick Byrd May 11, 2010

    is this a NO START problem with KOEO code or DOES START with KOEO code ? i know it sounds stupid but there is 2 flow charts for either problem . and 4.0L or 3.0L ?

  • yadayada
    yadayada May 11, 2010

    the chartt is in the factory emission repair manual.


5 Suggested Answers

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I've had a problem like that before and I replaced the computer and the problem was fixed. I believe that its the computer at fault. Good Luck

Posted on Dec 16, 2008

  • 379 Answers

SOURCE: 94 ford ranger dtc 542 and556

pull the fuel pump relay out , if pump stops , try replacing the relay . no doubt you have already fixed it seeing how old this post is :)

Posted on Dec 27, 2008

  • 39 Answers

SOURCE: 2001 Chevy S-10 fuel pump circut

no that is not true. i have a sonoma and when i changed the fuel pump it was on its own circuit. the only special thing about the fuel pump is that it is a one piece assembly with the fuel level sending unit. so if you have to replace the sending unit you have to buy a whole new pump.

Posted on Mar 13, 2009

  • 21990 Answers

SOURCE: i have a 2002 hyundai

remove the sender unit and check the connection pipes to the pump ,think you will find the problem here

Posted on Jun 15, 2010

  • 4803 Answers

SOURCE: starter motor went out on

  • Code 542 indicates one of the following conditions:

Engine Starts:

· Fuel Pump secondary circuit shorted to power

· Fuel pump relay contacts always closed

· Open in fuel pump monitor (FPM) circuit between ECU and connection to POWER TO PUMP circuit

· Heated Exhaust Gas Oxygen (HEGO) sensor shorted to power

· faulty ECU

Engine Does Not Start:

· Open inertia switch or inertia switch circuit

· Open in or between ECU and fuel pump (This includes open in fuel pump brushes/windings)

· faulty ground connection at fuel pump

The easiest way to check this circuit is to go to the fuel pump relay. If the relay clicks when the key is turned to the "RUN" position, then the inertia switch circuit is ok.

The Pink/Black wire starts from the fuel pump relay and goes two directions. One side goes back to the fuel pump. The other side is the fuel pump monitor circuit and goes to pin #8 at the ECU. This wire should only be hot for a second or two when the ignition is turned to the RUN position.

The fuel pump relay receives power on the Black/yellow wire. It comes from a fusible link at the power distribution center. This wire should be hot at all times.

If all the above is working as designed, them you probably have a bad fuel pump.

Posted on Feb 13, 2011

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Correct code P0504?

What Colorado do you have ? 2 wheel or 4 wheel drive ? Sport ,sport LS 3.5L , Z71, Z71 LS. etc. what size engine ? an does it have electronic throttle control ? I have factory service info an it is not showing that code .
DTC P0506

Circuit Description

The throttle actuator control (TAC) motor is controlled by the powertrain control module (PCM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P0506 Idle Speed Low
DTC P0507

Circuit Description

The throttle actuator control (TAC) motor is controlled by the powertrain control module (PCM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P0507 Idle Speed High
Cleaning the throttle body mite take care of it !
Cleaning Cleaning An Electronic Throttle Body Safely

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P2251 o2 bank 1 censor 1 negative current circut / open. What does this code mean? can car be driven?

Basically what this diagnostic trouble code (DTC) means is that the ground wire in the circuit of this O2/oxygen sensor has a short or an open circuit leading to the vehicles computer (PCM) and it is not giving the PCM the correct information it needs in order to make the vehicle run as efficient as it should. Your fuel injectors open and close at certain times to give the vehicle the fuel it needs. The function of the O2 sensor which is located in your exhaust pipe is to "read" how much fuel is going through the exhaust. The mare fuel that goes through the exhaust tells the O2 sensor that it's geting too much fuel which sends a singnal to the PCM to "tell" the fuel injector to not stay open as long, that it doesn't need that much fuel. If the O2 sensor detects not enough it telss the PCM to leave the fuel injector open longer. This is for fuel economy as well as for the enviroment. In answer to your question, yes the vehicle can be driven but you will not be geting the gas mileage you normally have due to your PCM not knowing how much fuel to allow the vehicle to have. Luckily you PCM will take over and open and close the injector to what it thinks is best to keep the vehicle running. It kind of over rides itself in order to keep the car running instead of depending on readings from your sensors. I hope this helps you better understand what the funtion of the O2 sensor is and why this DTC is happening. Below is a description for you as well. I will add one more thing though. If you do continue to run your vehicle like it is, it will give less life to your spark plugs and cat. converter.


Dec 29, 2011 | 2006 Hyundai Elantra

1 Answer

1996 pontiac firebird 5.7 liter engine light on po1441

Two choice dudes code there...

DTC P0441 - Evaporative Emission (EVAP) Control System Incorrect Purge Flow
EVAP emission canister purge is contolled by a valve which allows engine vacuum to pull stored fuel vapors from fuel tank into the engine to be burned, rather than be vented to atmosphere. A vacuum switch is used to detect when flow exists. If the PCM commands purge and sees that the switch is closed (indicating no detected purge flow) P0441 is set.
With a P0441 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:
  • Common Chrysler fix - Replace Leak Detection Pump / LDP
  • Repair damaged EVAP lines or canister
  • Repair open or short in voltage feed circuit to Purge Solenoid
  • Repair open in PCM purge command circuit
  • Replace purge Solenoid
  • Replace vacuum switch
  • Repair restriction in Evap line or canister or soleniod
  • Repair resistance in purge connector
  • Replace PCM

DTC P1441 - Evaporative Emission (EVAP) System Flow During Non-Purge.
ost generally caused by a purge valve stuck open. the only way to diag for sure is with a gm tech 2 scan tool and a smoke machine. but if dont mind spending a few bucks as a good quess. Replace the purge valve.

Hope this helps.

Jul 28, 2011 | 1996 Pontiac Firebird

1 Answer

How do I fix code P1237 on ford taurus sel

P1237 - Fuel Pump Secondary Circuit Malfunction

Electronic Returnless Fuel Systems (ERFS) utilize a Fuel Pump Driver Module (FPDM) to control fuel pressure. The PCM uses a Fuel Rail Pressure Sensor (FRP) for feedback. The PCM outputs a duty cycle to the FPDM to maintain the desired fuel rail pressure. During normal operation, the PCM will output a FP duty cycle from 5% to 51%. The FPDM will run the fuel pump at twice this duty cycle, e.g. if the PCM outputs a 42% duty cycle, the FPDM will run the fuel pump at 84%. If the PCM outputs a 75% duty cycle, the FPDM will turn off the fuel pump.

If the FPDM does not out any diagnostic signal, (0 or 100% duty cycle), the PCM sets a P1233 DTC. This DTC is set if the FPDM loses power. This can also occur if the Inertia Fuel Switch is tripped.

If the FPDM outputs a 25% duty cycle, it means that the fuel pump control duty cycle is out of range. This may occurs if the FPDM does not receive a valid control duty cycle signal from the PCM. The FPDM will default to 100% duty cycle on the fuel pump control output. The PCM sets a P1235 DTC.

If the FPDM outputs a 75% duty cycle, it means that the FPDM has detected an open or short on the fuel pump control circuit. The PCM sets a P1237 DTC.

Keep us updated.

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1 Answer

1994 Chevrolet 2500 Trouble codes. I have a 94 Chevy 2500, it flashes error 3 across the dummy screen with the truck mileage. I hooked it up to a diagnostic code reader, I got the following codes: 12:...

DTC 12 -
When terminals "A" and "B" have been connected, the ignition switch turned to the "ON" position with the engine not operating, the MIL (Service Engine Soon) should flash DTC 12 three times consequently. This will be the following flash sequence: "flash, pause, flash-flash, pause, flash, pause, flash-flash, pause, flash, pause, flash-flash." DTC 12 indicates that the control module diagnostic system is operating properly. If DTC 12 is not indicated, and a fault is present within the diagnostic system itself, it should be addresses by consulting the appropriate diagnostic chart in this section.

The MIL (SES) will indicate a diagnostic trouble code (DTC) three times if a DTC is present, or it will simply continue to output DTC 12. If more than one DTC has been stored in the control module memory, the DTC(s) will be displayed from the lowest to the highest with each DTC being displayed three times.

DTC 32 - Exhaust Gas Recirculation (EGR) Error
EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of the exhaust gas. EGR position signal is also monitored to verify EGR movement.

The EGR relies on a certain amount of exhaust back pressure to work properly. Now that you have lowered the back pressure, it can't work. Have you tried a new EGR valve? You may need a service manual with an EGR diagnostic chart to make sure, but I think the duals are the problem. Plus the O2 sensor is only looking at one side of engine instead of both.

Keep in midn this procedure to Clearing Diagnostic Trouble Codes:
To clear the DTC's from memory of the control module, either to determine if the malfunction will occur again or because the repair has been completed, the Tech 1 Scan Tool should be used to clear the DTC's. If a Tech 1 Scan Tool is not available the following must be perform'd when all repairs have been completed. This will allow all DTC's to be cleared:
1. Ignition "OFF."
2. Ground diagnostic terminal "A" to "B" of DLC (Data Link Connector).
3. Ignition "ON."
4. Fully apply brake pedal.
5.Fully apply accelerator pedal.
6. Check MIL (Service Engine Soon) for DTC 12.
7. Release brake pedal.
8. Release accelerator pedal.
9. Check MIL (Service Engine Soon) for DTC 12.
10. Turn ignition "OFF."
11. Remove Jumper from DLC connector.

NOTICE: To prevent control module damage, the key must be "OFF" when disconnecting or reconnecting module power.

Good luck.

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1 Answer

Sometimes my car won't start when i turn it off then when I am driving it turns off. Its a 1999 300M

Maybe it is problem with fuel, or fuel filter or pump…. Try with Diagnostic Trouble Codes (DTC)
  1. Cycle the ignition key On – Off – On – Off – On within 5 seconds.
  2. The Odometer will show the P-Code for the DTC code number. (send me a code if you don’t have chart with DCT’s)
  3. If no DTC’s present, the cluster will display one of two texts: “P1684” and “done” or only “done” .
    1. “P1684” is only a status and indicates that the PCM memory has been cleared within the last 50 ignition cycles and does not indicate a problem
    2. “done” indicate that no DTCs are present and the procedure is complete.

May 03, 2009 | 1999 Chrysler 300M

2 Answers

Replaced fuel pump in 1998 for ranger

Diagnostic Trouble Code (DTC) P0232 indicates that the powertrain control module (PCM) detected the FPM circuit voltage was high when the fuel pump was commanded off. The FPM circuit is wired to a pull-up voltage inside the PCM. The FPM circuit will go high if, with the key on and the fuel pump commanded off, the FPM/FP PWR circuit loses its path to ground through the fuel pump. The FPM circuit will also be high if the FPM/FP PWR circuit is shorted to power.
Possible causes:
No Start:
Inertia fuel shutoff (IFS) switch not reset or electrically open.
Open circuit between the fuel pump and FPM circuit connection to the FP PWR circuit.
Poor fuel pump ground.
Fuel pump electrically open.
Diagnostic Trouble Code (DTC) P0102 indicates the MAF sensor signal went below 0.39 volt (refer to Voltage to Mass Air Flow Conversion Table at beginning of this Pinpoint Test) sometime during normal engine operation (Continuous) or during Key On Engine Running (KOER) Self-Test.
Did you have the MAF unplugged?

Feb 18, 2009 | 1998 Ford Ranger SuperCab

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