Fault code P0704 is called “Clutch Pedal Position (CPP) Switch Input Circuit Malfunction” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0704
If your OBD-II equipped vehicle has stored code P0704. This means that the transmission control module (PCM) has detected a fault in the clutch switch input circuit. This code applies only to vehicles equipped with a manual transmission.
The PCM controls certain manual transmission functions. Shifter position and clutch pedal position are among these functions. In some models, turbo input and output speeds are also monitored to determine the degree of clutch slippage.
The clutch is the mechanical clutch that connects the engine to the transmission. When the clutch master cylinder is depressed, hydraulic fluid is pushed into the slave cylinder. The slave cylinder actuates the clutch pressure plate. Allowing you to engage and disengage the engine from the transmission as needed.
The main function of the clutch switch is to act as a safety feature to prevent the engine from starting when the transmission is inadvertently engaged. The PCM and other controllers also use input from the clutch switch for various engine control calculations. These include automatic braking functions, as well as for implementing hill-hold.
Diagnostic code DTC P0704 is set when the clutch pedal position switch (CPP) signal is not received by the control module. This signal refers to a yes/no signal, the computer either receives a voltage signal or it does not.
Symptoms of vehicle malfunctions
The main signal that an error P0704 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- Check engine control lamp on the control panel will light up (the code will be recorded in the memory as a fault).
- Increased fuel consumption.
- Poor engine starting.
- Excessive engine speed at idle.
- Traction control system may be disabled.
A stored code P0704 may cause various vehicle control, safety and traction functions to fail. For this reason, this error should be considered serious.
Factors that can cause this error code
The error code P0704 can mean that one or more of the following problems have occurred:
- Faulty or damaged clutch pedal limit switch.
- Worn clutch pedal lever or clutch lever bushing.
- Improperly adjusted clutch switch.
- Short-circuited, broken wiring or connectors in clutch switch circuit.
- Poor electrical connection in clutch switch circuit.
- Fuse or fusible link is blown.
- Faulty PCM or other control module, also possible programming error.
How to fix or reset OBD-2 code P0704
Some suggested steps for troubleshooting and fix the error code P0704:
- Inspect the wiring for damage, abrasions, breaks, and shorts. If wiring is damaged, repair or replace it.
- Remove any diagnostic trouble codes from the PCM, and test drive to see if diagnostic trouble code P0704 returns.
- Check if the clutch pedal limit switch is properly adjusted.
- If the switch is properly adjusted but the error appears again, you may need to replace the switch.
- If everything is correct, the PCM may need to be replaced and reprogrammed.
Diagnose and repair of problems
To rule out all variants of error P0704, visually inspect the clutch switch wiring. Check all system fuses and replace blown ones if necessary. Also check the battery under load, cable connections, and alternator power.
Locate the diagnostic connector, plug in the scanner and get all the stored codes and data. Write this information down, as it may help you in further diagnosis. Delete the codes and test-drive the vehicle to see if the P0704 code appears again after resetting.
Check voltage
Check the voltage on the clutch switch input circuit. If there is voltage in the input circuit, depress the clutch pedal and check the voltage in the output circuit. If there is no voltage on the output circuit, the clutch switch may be defective or misadjusted.
Check that the clutch articulation arm and pedal lever are mechanically sound. Check the clutch pedal bushing for play.
If voltage is present on both sides of the clutch switch when the pedal is depressed, check the clutch switch input circuit on the PCM. If the input signal to the PCM is present, a faulty PCM or programming error may be the cause.
If no clutch switch input signal is present at the PCM connector, disconnect all associated controllers. Use a multimeter to check the resistance for all circuits in the system. If necessary, repair or replace closed or open circuits.
It is a good idea to check the system’s fuses with the clutch pedal depressed when the P0704 error occurs. Fuses that may seem normal when first tested may fail when the circuit is under load.
Often a worn clutch hinge arm or clutch pedal bushing can be misdiagnosed as a faulty clutch switch.
On which vehicles does this problem occur most frequently
Fault code P0704 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Alfa Romeo
- Audi
- Chery (IndiS, Kimo, Tiggo)
- Chevrolet (Camaro, Silverado)
- Chrysler (300M)
- Citroen (C4)
- Dodge
- Fiat (Albea, Doblo, Ducato, Punto)
- Ford (Focus, Fusion, Transit)
- Honda
- Hyundai (Santa Fe, Solaris, Starex, ix35)
- Jeep (Grand Cherokee)
- Kia (Cerato, Rio, Sorento, Sportage)
- Mazda (3, 6)
- Mercedes-Benz
- Opel (Astra, Vectra, Zafira)
- Peugeot (206, 207, 307, Partner)
- Skoda (Octavia)
- Ssangyong (Kyron)
- Volkswagen (Passat)
- GAZelle (Next)
- UAZ (Hanter, Patriot, ZMZ 409)
Fault code P0704 can sometimes be found with other errors. The most common are the following: P0645, P0646, P0647, P0740, P0741, P0742, P0743, P0744.
