How is fault code P0704 fixed?

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read the codes and watch the clutch switch live data on a scan tool while a helper presses and releases the pedal. The reading should flip cleanly between pressed and released. If it sticks or jumps about, you've found your fault 2. Get under the dash and check the switch is actually being contacted by the pedal at the right point. Loose mountings and bent brackets are common, and a tweak of the adjustment fixes a fair few of these 3. Unplug the connector at the switch and look for green corrosion, bent pins or oil contamination from a leaking clutch master cylinder 4. Test the switch with a multimeter set to continuity, it should change state as you operate it by hand. A switch that reads the same in both positions is dead 5. Back-probe the wiring and check you've got voltage at the switch with the ignition on, then trace the circuit for breaks if the voltage is missing 6. If the switch, wiring and voltage all check out and the code keeps coming back, only then start looking at the PCM

Clutch Switch Input Circuit Malfunction

Jump to the fix

Severity

High

Can I keep driving?

Avoid extended driving; visit a service soon.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read the codes and watch the clutch switch live data on a scan tool while a helper presses and releases the pedal. The reading should flip cleanly between pressed and released. If it sticks or jumps about, you've found your fault 2.

PPowertrain
0Generic code
7Transmission
04Sequence number

What does it mean?

P0704 Clutch Pedal Position (CPP) Switch: The clutch switch is a normally closed switch (clutch pedal released). The control module which could be the TCM (Transmission Control Module), BCM (body control module), or PCM (powertrain control module body control module (BCM) detects an ignition voltage on the clutch switch circuit when the clutch switch is closed. The control module detects 0 volts on the clutch switch circuit when the clutch switch is open (clutch pedal depressed).

When the clutch switch is closed, clutch released, the control module detects a predetermined voltage signal and sends a serial data message to the engine control module (ECM). This DTC determines if the Transmission Clutch switch has failed by looking for a clutch switch transition during a predetermined drive cycle.

NOTE: Whenever diagnosing a 700 series DTC (Diagnostic Trouble Code) with a transmission, transfer case or other driveline components, check for diagnostic trouble codes (DTCs) under chassis and body systems, not just under “P” or powertrain/engine or emission control type codes. Module communications DTCs are “U” codes. These are most often found when looking for DTCs under chassis or body systems.

Chassis related codes are labeled “C” and body system related codes are labeled “B” codes and these can cause drivetrain issues if they affect a sensor that is also used by the heating and air conditioning system. Figure 1 Brake/TCC Switch Wiring Diagram The DTC P0704 diagnostic code will set when CPP (Clutch Pedal Position) switch signal is not received by the control module: BCM, PCM, TCM, ECM). This is a high/low signal, the computer either receives a voltage signal or not.

Symptoms

Likely causes

How to fix it

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This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.