Combined Inverter and DC/DC Converter

Delphi Combined Inverter and DC/DC Converter (CIDD) is our OE solution for hybrids (HEV), plug-in hybrid electric (PHEV), and battery electric vehicles (BEV) that delivers maximum power density in a lighter, smaller, cost-effective package.

As the market for electric cars rapidly increases, independent aftermarket garages will need the right replacement part for the repair. That’s why Delphi is offering exact OE performance with our power electronic aftermarket parts.

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What is the difference between an inverter and DC/DC converter in an electric vehicle?

Much like how internal combustion engines and alternators work together on conventional vehicles, hybrid cars and electric motors use inverters and converters to manage power to and from the battery pack to the motors and other on-board systems.

Inverters transform direct current (DC) from the battery into alternating current (AC) to power the vehicle. Inverters also control the motor and convert it to a generator, transferring braking energy back into the battery.

Converters control the DC voltage from the battery, either stepping it up or down based on the system and the power needed. DC/DC converters usually step down the high voltage from the battery pack to the 12-volts used by radios, headlights, and more.

An OE solution for aftermarket power electronics

Inverters and converters work together to manage the vehicle's electric drive and accessory systems. However, many of today’s inverters and converters can be complex, expensive, and prone to failure from excessive heat. They are also heavy and take up a lot of room on the vehicle, compromising both trunk and passenger compartment space. Delphi OE solution combines the inverter and DC/DC converter into one unit.

Delphi CIDD is cost-effective and saves vital weight and space in hybrids (HEV), plug-in hybrid electric (PHEV), and electric vehicles (EV). And by leveraging patented OE technology - Viper-enabled inverter’s double-sided cooling - it tackles the issue of overheating, allowing higher power outputs from a smaller package and increased range.

Combined Inverter and DC/DC Converter (CIDD)

Enhances durability and reliability through features designed to withstand under the hood and environmental factors such as debris and temperature extremes.
Improves voltage distribution functionality, enabling both low-side and high-side power for everything from headlights to power steering and air conditioning systems.
Provides maximum packaging flexibility and space savings by moving the DC/DC unit from its standard location in the rear to the front of the vehicle.
Enables better power range and minimizing power losses through the elimination of cabling, cooling hoses, connections, and housings, all while simplifying maintenance and repair.

To learn more about OE quality aftermarket EV parts you can trust, contact your Delphi representative today.

The Delphi Difference

100 years of OE experience, supplier to the world’s top automakers
OE heritage and knowledge built into every aftermarket part
Comprehensive portfolio for a wide range of vehicles and model years
Streamlined SKUs for easy inventory management
Support through tools, tips and training

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4 min read

How to diagnose a faulty knock sensor

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Sensors Vehicle Electronics & Engine Management Need to Know Distributors Shop Owners Technicians 4 min read

Resource Highlights

A faulty knock sensor can seriously affect an engine’s condition – but there can be plenty of warning signs that indicate where the issue lies. Here we’ll explain how to diagnose a knock sensor problem and advise on the best fix.

What is a knock sensor

Knock sensors detect engine vibration or detonation. Learn in detail what they are and how they work here, but in a nutshell, they send a signal to the engine control module (ECM) to prevent engine knock.

A faulty knock sensor can seriously affect an engine’s condition. Here we’ll explain how to diagnose the symptoms and advise on the best fix.

What does the knock sensor do?

The knock sensor is designed to detect signs of engine ‘knock’ – pre-ignition and other explosions outside of the main firing process.

The knock sensors work by containing a stack of piezoelectric crystals that create signals in voltage when compressed by engine knock. These signals are sent to the ECU, which then optimises the air/fuel mix to prevent further occurrences. This achieves maximum vehicle performance and fuel economy, as well as reducing emissions.

Is the knock sensor important?

Yes, a knock sensor is essential for preventing engine knock. These detonations can severely damage an engine, causing it to run inefficiently, with less power and significantly reduce its lifespan.

What are the most common symptoms of a faulty knock sensor?

There are some signs to look out for that a knock sensor could be faulty. These telltale signs tend to affect engine performance and overall condition. Any of the symptoms below could signal that the knock sensor needs a look.

‘Check engine’ light is on

Any problem picked up by a sensor – or any problem with the sensor itself – is relayed to the ECU. The ECU then signals the driver’s attention to a problem by illuminating the ‘check engine’ light.

Engine knocking

The knock sensor is equipped to deal with engine knock by having the ECU adjust the air/fuel mix in the cylinder, thus reducing the amount of misfiring and the amount of knock. Increased engine knock – an excessive knocking or vibrating – may mean the sensor isn’t functioning correctly to send that signal.

Decreased acceleration

If the knock sensor isn’t working, the ECU can’t tell if it’s got the right mix of air and fuel in the cylinder. To protect the engine, the ECU will hamper the ignition timing, protecting the engine from unnecessary damage but removing the oomph from the engine.

Reduced engine power

The loss of power isn’t limited to trouble accelerating. The vehicle’s onboard electronics are acting to preserve the engine and prevent further damage, which means reduced torque throughout the journey.

Lower fuel economy

With its acceleration reined in, the vehicle’s fuel economy will drop too, as the engine isn’t burning the fuel as efficiently as it could be if the knock sensor were operational.

Find knock sensors and a selection of OE parts in the Delphi online catalogue

Why do knock sensors fail?

Knock sensors can break down for a variety of different reasons relating to installation, maintenance and performance during use.

Issues could be caused by incorrect installation or use of a faulty component, such as a knock sensor with bad wiring.

Excessive vibration could have shaken loose a connection, caused damage to the sensor or could be preventing the sensor from doing its job.

How to diagnose a knock sensor

If any of the above common symptoms are occurring, it’s recommended to test the knock sensor to see whether or not there is a fault. There are several ways to do this.

Test with a multimeter

Use this to check the wiring of the sensor to the control unit. Connect to the wiring harness and then measure the resistance values. A normal resistance reading should be around the 0.1 ohms mark. Any wide deviation would point to a wiring harness fault.

Test with an oscilloscope

With the engine running and idle, connect the test probes of the oscilloscope to the knock sensor and then record the signal waveform it produces. If it fails to display a knock signal, it suggests a fault. As a further test, while still recording, tap gently against the engine block near the sensor. If that knocking isn’t detected either, you have a defective sensor or circuit on your hands.

Test with a scan tool

This is a common and straightforward way to diagnose a faulty knock sensor. With a diagnostic scanner, you can quickly check for error codes stored in the ECM. A code related to a knock sensor would indicate a fault. You may wish to then test the sensor with the methods outlined above.

Error code is stored

Your diagnostic scanner or code reader may pick up the following codes which suggest a knock sensor fault.

P0325: Knock Sensor Malfunction (Sensor 1, Bank 1), indicating a problem with the electrical circuit of the knock sensor on bank 1.
P0326: Knock Sensor Range/Performance (Sensor 1, Bank 1), indicating that the signal from the knock sensor on bank 1 is outside the normal range.
P0327: Knock Sensor Low Input (Sensor 1, Bank 1), indicating that the signal from the knock sensor on bank 1 is weak.
P0328: Knock Sensor High Input (Sensor 1, Bank 1) indicating that the signal from the knock sensor on bank 1 is too high.

Knock sensor replacement

If you’ve identified you’ve got a faulty knock sensor, it’s recommended to replace it rather than attempt a repair. Replacing a knock sensor is relatively straightforward. To learn how, follow our simple 4-step guide.

FAQs about knock sensors

How serious is a faulty sensor code?

A faulty sensor code indicates a serious problem that should be looked at by a vehicle technician as soon as possible.

Can you drive with a faulty knock sensor?

Never drive with a faulty knock sensor. Without a functioning knock sensor, the engine won’t be able to know how to adjust ignition timing or mix air and fuel correctly, potentially leading to significant damage to the engine and exhaust system.

How much does a knock sensor cost?

A replacement knock sensor plus labour should cost anything from £150, depending on the make and model of the vehicle. If the sensor is located in a hard to reach area, more engine components will need to be removed, adding more labour cost.

Could a faulty knock sensor cause high input?

Yes, there is a specific error code for this fault – P0328. It’s recommended to replace the knock sensor and run a diagnostic again to check that the fault has cleared.