Pressure control value 270D - 2004 Mercedes-Benz C270 CDI

Question edited for clarity.
Question moved to model category.

Jeff provides a great answer.

• Jeff Armer Jul 24, 2022
• When you push the A/C button on the climate control panel does it light ? Do you hear compressor clutch kick on? How are you measuring this? What wire gray or black,this sensor only has five volts from the PCM- engine computer . Five volt reference voltage from five volt ref. #2 circuit .
  
  Does your vehicle have;
  HVAC Systems - Manual
  HVAC Systems - Automatic
• 
  Jeff Armer Jul 24, 2022
  A/C Refrigerant Pressure Sensor
  The A/C refrigerant pressure sensor is a 3 wire piezoelectric pressure transducer. A 5-volt reference, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0-5 volts. When the A/C refrigerant pressure is low, the signal value is near 0 volts. When the A/C refrigerant pressure is high, the signal value is near 5 volts. The PCM converts the voltage signal to a pressure value.
  
  The A/C refrigerant pressure sensor protects the A/C system from operating when an excessively high pressure condition exists. The PCM disables the compressor clutch if the A/C pressure is more than 2957 kPa (429 psi). The clutch will be enabled after the pressure decreases to less than 1578 kPa (229 psi).
  
  A/C Low Pressure Switch
  The A/C low pressure switch protects the A/C system from a low pressure condition that could damage the A/C compressor or cause evaporator icing. The HVAC control module applies 5 volts to the A/C low pressure switch signal circuit. The switch will open when the A/C low side pressure reaches 138-172 kPa (20-25 psi). This prevents the A/C compressor from operating. The switch will then close when A/C low pressure side reaches 275-317 kPa (40-46 psi). This enables the A/C compressor to turn back ON.
  

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Do the A/C pipes going in through the fire wall get cold ( icy) ? Temp blend dood actuator possibly .Does it have A/C system in the back as well ? Auxiliary - does it get cold ?

Air Temperature Actuator
The air temperature actuator is a 3 wire bi-directional electric motor. Ignition 3 voltage, ground and control circuits enable the actuator to operate. The control circuit uses a 0-12 volt linear-ramped signal to command the actuator movement. The 0 and 12 volt control values represent the opposite limits of the actuator range of motion. The values in between 0-12 volts correspond to the positions between the limits.
When the HVAC control module sets a commanded, or targeted, value, the control signal is set to a value between 0-12 volts. The actuator shaft rotates until the commanded position is reached. The module will maintain the control value until a new commanded value is needed.
Have you hooked up manifold gauge's to check pressures ?

Does the Vehicle start an run ? What engine does it have ? 4.0 or 4.6 L You vehicle has electronic returnless fuel system , Fuel rail pressure sensor , FPDM - fuel pump driver module . The fuel pump driver module controls the fuel by pulse width modulation
Pulsewidthmodulation (PWM) is a powerful technique for controlling analog circuits with a processor's digital outputs. PWM is employed in a wide variety of applications, ranging from measurement and communications to power control and conversion. The PCM - engine computer uses the fuel rail pressure sensor input to send commands to the FPDM .
What code ? P0--- what ?



P0190 - Fuel Rail Pressure (FRP) Sensor Circuit Malfunction Description: The comprehensive component monitor (CCM) monitors the FRP sensor to the powertrain control module (PCM) for VREF voltage. The test fails when the VREF voltage from the PCM drops to a voltage less than a minimum calibrated value. Possible Causes:

• VREF open in harness.
• VREF open in sensor.
• Vacuum leaks.

Diagnostic Aids: Verify a VREF voltage between 4 and 6 volts. Application Key On Engine Off Key On Engine Running Continuous Memory Fuel rail pressure temperature (FRPT) sensor - GO to DD26 GO to DD26 Fuel rail pressure (FRP) sensor only - - GO to DD1 Fuel rail pressure (FRP) and fuel rail temperature (FRT) sensors - - GO to DD1


P0191 - Fuel Rail Pressure (FRP) Sensor Circuit Performance Description: The comprehensive component monitor (CCM) checks the FRP for acceptable fuel pressure. The test fails when the fuel pressure falls below or exceeds a minimum/maximum calibrated value for a calibrated period of time. Possible Causes:

• High fuel pressure.
• Low fuel pressure.
• Damaged FRP sensor.
• Excessive resistance in the circuit.
• Vacuum leaks.
• Low or no fuel.

Diagnostic Aids: A FRP PID value during key on engine running (KOER) of 138 kPa (20 psi) to 413 kPa (60 psi) is acceptable. Application Key On Engine Off Key On Engine Running Continuous Memory Fuel rail pressure temperature (FRPT) sensor GO to DD34 Fuel rail pressure (FRP) sensor only GO to DD9 Fuel rail pressure (FRP) and fuel rail temperature (FRT) sensors GO to DD9


P0192 - Fuel Rail Pressure (FRP) Sensor Circuit Low Input Description: The comprehensive component monitor (CCM) monitors the FRP sensor circuit to the powertrain control module (PCM) for low voltage. If voltage falls below a calibrated limit for a calibrated amount of time during testing, the test fails. Possible Causes:

• FRP signal shorted to SIG RTN or PWR GND.
• Damaged FRP sensor.

Diagnostic Aids: A FRP PID value during the key on engine off (KOEO) or key on engine running (KOER) less than 0.3 volt indicates a hard fault. Application Key On Engine Off Key On Engine Running Continuous Memory Fuel rail pressure temperature (FRPT) sensor GO to DD26 GO to DD26 GO to DD39 Fuel rail pressure (FRP) sensor only GO to DD1 GO to DD1 GO to DD14 Fuel rail pressure (FRP) and fuel rail temperature (FRT) sensors GO to DD1 GO to DD1 GO to DD14


P0193 - Fuel Rail Pressure (FRP) Sensor Circuit High Input Description: The comprehensive component monitor (CCM) monitors the FRP sensor circuit to the powertrain control module (PCM) for high voltage. If voltage exceeds a calibrated limit for a calibrated amount of time during testing, the test fails. Possible Causes:

• FRP signal shorted to VREF or VPWR.
• FRP signal open.
• Damaged FRP sensor.

Diagnostic Aids: An FRP signal high condition can be caused by any number of conditions, including a short on FRP signal to VREF, a more positive voltage level, an open FRP signal or signal return. The FRP signal line is pulled up by the PCM and VREF at the sensor, and down by the sensor through SIGRTN. Application Key On Engine Off Key On Engine Running Continuous Memory Fuel rail pressure temperature (FRPT) sensor GO to DD26 GO to DD26 GO to DD39 Fuel rail pressure (FRP) sensor only GO to DD1 GO to DD1 GO to DD14 Fuel rail pressure (FRP) and fuel rail temperature (FRT) sensors
P1233 Ford Fuel Pump Driver Module Diagnostics and Repair

FPDM Live

NO , there is not a fuse just for those two thing's ! There are two power supply's for the whole insturment cluster . You could need a new cluster or the ECM isn't sending this info. to the cluster . Could have DTC'S - diagnostic trouble codes stored in the PCM or the insturment cluster . Without knowing how this works (insturment cluster gets it's info.) Your best bet , take it to a qualified repair shop that has the knowledge and test equipment to diagnose this problem.
Engine Oil Pressure Gage
The instrument panel cluster (IPC) displays the engine oil pressure as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 psi (0 kPa) or below if:
• The ECM detects a malfunction in the engine oil pressure sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.
For the 4.2L LL8, the ECM uses an engine oil switch that is open when the oil pressure is normal and closed when the oil pressure is low. At normal pressure, the engine oil pressure gage will display 275 kPa (40 psi). At low pressure, the gage will go to 0 kPa and the low pressure warning will be displayed in the driver information center (DIC). At high pressure, the gage will display 551 kPa (80 psi). Any values between these three values are calculated values determined by the ECM.

Voltmeter
The instrument panel cluster (IPC) displays the vehicle voltage based on the information from the body control module (BCM). The IPC uses the serial data information from the BCM to provide a voltage level indication on the voltmeter.

DTC P0521: Engine Oil Pressure (EOP) Sensor Performance

DTC P0522 Engine Oil Pressure (EOP) Sensor Circuit Low Voltage
DTC P0523 Engine Oil Pressure (EOP) Sensor Circuit High Voltage

Volt Gage Inaccurate or Inoperative
2
Install a scan tool.
Turn the ignition ON, with the engine OFF.
With the scan tool, perform the instrument panel cluster (IPC) gauges output control.
Does the volt gauge move up and down when commanded?

Did you read and clear the DTC after replacing the part?

2-4 or 2 control pressure rationality problems this means internal hydraulic pressures do not agree with set values created by the computers software program. most likely cause is a internal leak (pressure loss)

P0234 Description
The boost pressure sensor responds to pressure changes in the intake manifold. This pressure is created by the turbocharger and changes with accelerator pedal position (APP) and engine speed. The engine control module (ECM) uses this information to assist in diagnosis of the barometric pressure (BARO) sensor and to provide engine overboost protection. The boost pressure sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) supplies 5 volts to the boost pressure sensor on the 5-volt reference 2 circuit, and provides a ground on a low reference circuit. The boost pressure sensor provides a signal to the ECM on a signal circuit relative to the pressure changes. The ECM monitors the boost pressure sensor signal for voltage outside of the normal range. The ECM calculates a predicted value for the boost pressure sensor. The ECM then compares the predicted value to the actual signal.


Read more: http://engine-codes.com/p0234.html#ixzz2e2DssWbP

Hello, this vehicle doesnt use a cycling switch. it uses a pressure sensor. this compressor runs all the time. there is a expansion valve that controls the amount of freon entering the evap core. here is how the compressor uses a pressure senor

The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5-volt reference, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0-5 volts. . When the A/C refrigerant pressure is low, the signal value is near 0 volts. When the A/C refrigerant pressure is high, the signal value is near 5 volts.
The A/C refrigerant pressure sensor protects the A/C system from operating when an excessively high or low pressure condition exists. The PCM disables the compressor clutch under the following conditions:
• A/C pressure is more than 2979 kPa (432 psi). The clutch will be enabled after the pressure decreases to less than 1620 kPa (235 psi).
• A/C pressure is less than 179 kPa (26 psi). The clutch will be enabled after the pressure increases to more than 207 kPa (30 psi).

The ECT (Engine Coolant Temperature) sensor is a thermal variable resistor (also known as a "thermistor"). The ECT delivers a signal to the THW terminal of the Engine Control Module (ECM) which varies with engine coolant temperature. The ECM uses this signal to control the fuel injection system, the overdrive operation on vehicles equipped with electronically controlled overdrive transmissions, spark timing control, idle speed control, fuel pressure control system (if equipped), heated oxygen sensor system (if equipped) and EGR systen (if equipped)

Ther first code ECM-6805 TURBOCHARGER (TC) CONTROL VALVE DIAGNOSTIC TROUBLE CODE (DTC) INFORMATION If engine speed (RPM) is above 3500 rpm and the engine is operating at a high load, and if the boost pressure (from the boost pressure sensor) is higher than a designated value, which at maximum boost pressure is approximately 20kPa (2.9psi) above normal boost pressure, this is interpreted as a fault and diagnostic trouble code (DTC) ECM-6805 is stored. Condition reduced boost pressure Possible source * hoses between turbocharger (TC) and turbocharger (TC) control valve respectively turbocharger (TC) control valve and pressure servo are loose or are blocked/damaged * faulty turbocharger (TC) control valve * faulty boost pressure control (BPC) valve pressure servo * sticking boost pressure control (BPC) valve Condition * none ECM-6805 TURBOCHARGER (TC) CONTROL VALVE PRESSURE TOO HIGH - PERMANENT/INTERMITTENT FAULT Checking the hoses and turbocharger (TC) control valve Check that the hoses between the intake manifold, pressure regulator and turbocharger (TC) control valve are not trapped, blocked or damaged. Check the turbocharger (TC) control valve by activating it. Check the alignment of the boost pressure control (BPC) valve pressure servo and the boost pressure control (BPC) valve and that they are functioning correctly and not sticking according to See: Component Tests and General Diagnostics\Boost Pressure Regulator, Checking/Adjusting Verification Hint: After carrying out the repair, check that the fault has been remedied. * Ignition off. * Reinstall connectors, components etc. * Disconnect the VCT 2000 from the data link connector (DLC). * Test drive the car and check that high boost pressure is obtained. * Connect the VCT 2000 to the data link connector (DLC). NOTE: Do not switch off the ignition before the VCT 2000 has been connected and the boost pressure has been tested with the smart tool. Read the boost pressure fault status When the boost pressure has been tested the display should show that the diagnostic is complete. the second code Symptoms You will likely not notice any serious drivability problems, although there may be symptoms. Possible Solutions The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures: Inspect for the following conditions: An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components: - The secondary ignition wires or coils - Any solenoids - Any relays - Any motors A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system. The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON. When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude. A high resistance on the ground circuit of the MAP sensor can cause this DTC to set. Any loss of vacuum to the MAP sensor can cause this DTC to set. the third code O2 sensor failure may not be displayed appropriatly