Porsche P9288 System Tester – Diagnostic Device 928 944 968 964 993

Great device, works smoothly and you can reset the airbag, check alarm contacts, and test PSD. Read EZK and LH. Test the throttle switch (TPS), coolant and oil temperatures. Faster to use than the official Piwis computer. All necessary connectors included. Made in the UK. We’re very happy with it. Limited stock, so be quick.

The P9288 System Tester is a modern diagnostic device for classic Porsche models from the late 1980s and 1990s. It is suitable for selected versions of the Porsche 928, 944, 968, 911 (964), and 911 (993).

The P9288 is a modern alternative to the original Porsche 9288 System Tester (Bosch KTS300/KTS301). It lets you read and clear fault codes, view live sensor data, and test electronic components. The device also supports various specialized diagnostic and adjustment functions.

The tester uses the Porsche-specific KWP1281 protocol via K- and L-lines. This diagnostic system cannot be read with ordinary universal OBD2 diagnostic equipment.

With automatic control unit recognition, a clear display, and free firmware updates, the P9288 is suitable for both professional Porsche specialists and owners who carry out maintenance and diagnostics themselves.

Suitable for

The P9288 supports the following Porsche models and model years:

• Porsche 928: 1988–1994

• Porsche 944: 1989–1991

• Porsche 968: 1992–1995

• Porsche 911 (964): 1989–1994

• Porsche 911 (993): 1995–1996, excluding US models from 1996

The tester supports various electronic control units, depending on the Porsche model and the equipment installed.

Important: Not every model has the same electronic systems. The available diagnostic functions may also vary by control unit and software version.

Alternative to the original Porsche 9288 System Tester

The P9288 was developed as a modern replacement for the original Bosch KTS300 with KTS301 Porsche module, also known as the Porsche 9288 System Tester or Bosch Hammer.

This original diagnostic equipment is now difficult to find and often expensive. In addition, the devices are decades old.

The P9288 offers the same type of factory diagnostic data, but with modern controls and additional practical benefits:

• Faster scanning of electronic control units.

• Automatic detection of installed control units.

• Fault messages displayed directly in plain language.

• Multiple current measured values displayed at once.

• Save diagnostic reports to a computer.

• Free firmware updates via USB-C.

This makes the P9288 a practical tool for servicing and diagnosing classic Porsche models.

Diagnostic functions

Read and erase fault codes

The P9288 can automatically scan electronic control units and display stored fault codes.

• Automatically search for installed control units.

• Identify which control units have stored fault codes.

• Display fault messages in plain language.

• View fault codes individually.

• Erase stored fault codes.

• Connect directly to a selected control unit.

Erasing fault codes does not fix the problem. If the cause is still present, the fault code may reappear.

View live sensor data

The tester can display current measured values from supported control units.

Depending on the vehicle and control unit, the following live data, among other values, is available:

• Engine speed

• Engine temperatures

• Sensor voltages

• Lambda signals

• Switch positions

• Other engine and system data

Multiple measured values can be displayed simultaneously, helping you spot anomalies more quickly during diagnosis.

Test electronic components

The actuator test function lets you control supported electronic components directly from the tester.

Depending on the control unit, these may include:

• Injectors

• Idle control valve

• Relays

• Electronic valves

• Central locking

• Heating valves

• ABS pump and solenoid valves

• Differential lock

This lets you check whether a component responds to the control signal.

Additional diagnostic and adjustment functions

Depending on the control unit, the P9288 also supports specialized functions, including:

• Idle adaptation

• CO adjustment

• Record knock signals

• Read ECU identification data

• Check electrical input signals

• Read codes

• Read saved vehicle data

Not all functions are available on every Porsche.

Supported Porsche systems

Porsche 928 – 1988 through 1994

The P9288 supports diagnostics for the following systems, if equipped:

• LH-Jetronic: electronic fuel injection

• EZK: electronic ignition control

• RDK: tire pressure monitoring system

• PSD: electronically controlled limited-slip differential

• Airbag: airbag control unit

• Alarm: alarm system

The PSD system can be used to read fault codes and activate differential control components, among other functions.

The RDK system can be used to check tire pressure sensor and wheel speed sensor data, among other things.

Porsche 944 – 1989 through 1991

The tester supports the following systems, if equipped:

• DME Motronic engine management

• Airbag

• Alarm

This can be used to investigate faults in the electronic engine management system, among other things.

Porsche 968 – 1992 through 1995

Supported systems:

• DME Motronic engine management

• Airbag

• Alarm

• Tiptronic automatic transmission

Supported Tiptronic control units provide access to fault codes, input signals, and solenoid valve tests, among other functions.

Porsche 911 (964 and 993)

The P9288 supports the following electronic systems, among others:

• DME Motronic engine management

• PDAS all-wheel drive and differential control

• ABS5 and ABS5-ABD

• Tiptronic

• Electronic heating control

• Airbag

• Alarm

The systems actually available vary by model, trim, and model year.

Save diagnostic reports via USB-C

A key advantage of the P9288 is the ability to save diagnostic data on a computer.

After scanning a vehicle, the detected control units and error messages can be saved as a text file.

• Export report as Results.txt.

• Connection via USB-C.

• The tester is recognized as a removable storage drive.

• No separate drivers are needed to read the report.

This is useful for workshops that want to save diagnostic data or share it with customers.

The device also has a logging function that can store technical communication data for further analysis.

Free firmware updates

The P9288 supports free firmware updates.

Updates are installed via a Windows computer and the USB-C connection. This allows the software to be updated and support for certain diagnostic functions and control units to be improved.

A connection to the vehicle is not required to install updates, except for specific updates to the internal USB software.

Connection and operation

The P9288 connects to the vehicle's diagnostic connector.

The required connection cables are included:

• OBD-type diagnostic cable

• OBD to 19-pin Porsche adapter cable

• USB-C cable

The device is powered via the vehicle's diagnostic connector. When connected to a computer, the tester is powered via USB-C.

No internal batteries are required, and the device does not have a separate on/off switch.

After switching it on, select the Porsche model. You can then scan all available control units or select a specific control unit directly.

To read and clear fault codes, it is generally sufficient to switch on the ignition. The engine usually needs to be running to view current engine data.

Safety: Actuator tests should normally be performed with the engine switched off. Always consult the official Porsche workshop documentation when working on safety-critical systems. Do not operate the tester while driving.

Benefits of the P9288 System Tester

• Modern alternative to the original Porsche 9288 System Tester.

• Developed for the Porsche-specific KWP1281 diagnostic protocol.

• Supports selected Porsche models from 1988–1996.

• Read and clear fault codes in plain text.

• View live sensor data and switch positions.

• Control electronic components individually.

• Automatic detection of installed control units.

• Save diagnostic reports via USB-C.

• Free firmware updates.

• All three required connection cables are included.

• Technical support with operation via our webshop.

Technical details

• Product: P9288 System Tester

• Type: Electronic diagnostic device

• Application: Classic Porsche models

• Models: 928, 944, 968, 911 (964), 911 (993)

• Model years: 1988–1996, depending on model and trim

• Diagnostic protocol: Porsche-specific KWP1281, K- and L-line

• Vehicle connection: OBD-type diagnostic cable or 19-pin Porsche adapter

• Computer connection: USB-C

• Power supply: Via vehicle or USB-C

• Battery: Not required

• Firmware: Updatable via Windows computer

• Updates: Free

• Diagnostic report: Results.txt

• Condition: New

Set contents:

• 1 × P9288 System Tester

• 1 × OBD-type diagnostic cable

• 1 × OBD to 19-pin Porsche adapter cable

• 1 × USB-C cable

Frequently asked questions

Is the P9288 a replacement for the original Bosch KTS300/KTS301?

Yes. The P9288 was developed as a modern alternative to the original Porsche 9288 System Tester with Bosch KTS300/KTS301. Available diagnostic functions depend on the vehicle and control unit.

Does the P9288 work with every Porsche 928 or 944?

No. According to the compatibility list, Porsche 928 models from 1988–1994 and Porsche 944 models from 1989–1991 are supported. Available diagnostic functions vary by model.

Can I read the Porsche 928 PSD differential control system?

Yes. The P9288 supports diagnostics of the PSD system in compatible Porsche 928 models. Differential control tests are also possible.

Can I read and clear fault codes with the P9288?

Yes. The tester can read and clear fault codes from supported electronic control units. Error messages are displayed in readable text.

Can I view live sensor data with the P9288?

Yes. Depending on the control unit, you can view engine speed, temperature, voltage, and other live data.

Do I need a computer to use the P9288?

No. The tester works independently for standard vehicle diagnostics. A Windows computer is only needed for software updates. You can also use a computer to view saved diagnostic reports.

Are all the connection cables included?

Yes. The P9288 comes with an OBD-type diagnostic cable, a 19-pin Porsche adapter cable, and a USB-C cable.

Can I get support if I have questions about how to use it?

Yes. If you have questions about connecting or operating the P9288, you can contact our online store.