How to Enter Bosch Dishwasher Diagnostic Mode

Quick Answer

To enter Bosch dishwasher diagnostic mode on 2015+ models (300/500/800 series): with the door open, press and hold the two leftmost buttons simultaneously for 3-5 seconds until the display changes. Close the door and the test cycle runs automatically, testing water inlet, heater, wash motor, and drain pump in sequence. Older models (SHU/SHV, pre-2010) use a 3-button rotating sequence - see the steps below.

Bosch dishwashers have a built-in diagnostic mode that tests every major component in sequence: water inlet, heater, wash motor, drain pump, door lock, and sensors. Accessing it can save you a $150 technician call. The entry method varies by model series: on most 300-800 series (2015 onward), hold the two leftmost buttons simultaneously for 3-5 seconds. On older models, a 3-button sequence is used. The diagnostic program runs automatically and stores fault codes that can be read from the display.

BoschDishwasherSeverity: lowDifficulty: intermediate

Time to Fix

15–90 min

Difficulty

intermediate

Parts Cost

—

Tools Needed

Paper and pen to record test results

Wrong code?

Not seeing DIAG on your display?

Select what your appliance is actually doing and we'll take you to the right guide.

service mode display on panel

SA NL

board communication failure

E92

all error codes reference

HUB

clearing error codes and resetting cycle

HUB

What Does the DIAG Code Mean?

Bosch diagnostic mode is a manufacturer-level test sequence built into the control board firmware. It differs from simply having an error code - diagnostic mode actively tests each component and records whether it passed or failed, giving you specific component-level information rather than just a symptom code. Understanding what was tested and what failed tells you exactly which part to order.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Need to read stored error codes for diagnosis40%

Intermittent fault that clears before technician visit24%

Preparing for DIY repair and need fault confirmation22%

Error code appeared then disappeared - want to confirm it14%

Can you reset a Bosch dishwasher to clear the DIAG code?

To exit diagnostic mode early, hold Start/Reset for 3-5 seconds. This aborts the test sequence and drains any water.

Tools Required for Diagnosis

Paper and pen to record test results

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Identify your Bosch model series

The diagnostic entry method differs between model generations. Find your model number on the label inside the door frame (left or right side). Models starting with SHPM or SHPK (2015 and newer 500/800 series) use the two-button hold method. Models starting with SHE (2010-2015 300 series) use a similar two-button method. Models starting with SHU or SHV (pre-2010) use a 3-button rotating sequence.

Enter diagnostic mode (2015+ models)

Read test results from the display

Frequently Asked Questions

What is the Bosch diagnostic mode button combination?

For most 2015 and newer Bosch dishwashers (300, 500, 800, and 800 Plus series), hold the two leftmost buttons on the control panel simultaneously for 3-5 seconds with the door open. The display will change or a light sequence will activate. Close the door to start the test sequence. For pre-2010 models (SHU/SHV series), the entry requires a 3-button sequence: press buttons 1, 2, and 3 in quick succession, then press 1, 2, and 3 again within 4 seconds.

How do I read Bosch diagnostic codes?

As each component test completes, the display shows a two or three digit code. A code of 0 or 00 typically indicates a passing test. Any other code identifies the component that failed using the same code system as regular error codes - E01 for the wash motor, E24 for the drain path, E15 for the float switch, and so on. Write down every non-zero result. Some models only show the final stored fault code rather than live results per test.

What is the difference between diagnostic mode and error codes?

Error codes appear automatically when the dishwasher detects a fault during a normal cycle. Diagnostic mode is a proactive test you initiate that actively tests each component in a controlled sequence. Error codes tell you a symptom; diagnostic mode pinpoints the specific component that failed. If a dishwasher has a vague or intermittent problem that does not consistently throw an error, diagnostic mode can surface the fault.

Stuck in diagnostic mode - how do I exit?

Hold the Start/Reset button (or Cancel button depending on your model) for 3-5 seconds. This stops the test sequence, drains any water that filled during testing, and returns the dishwasher to normal standby mode. If buttons are unresponsive, turn off the circuit breaker for 30 seconds to force-exit.

Can I damage the dishwasher by running diagnostic mode?

No. Diagnostic mode runs only the same operations the dishwasher performs during normal use - filling with water, circulating, heating, and draining. The only practical concern is that the dishwasher must be properly installed with hoses connected before running diagnostics. Do not run diagnostic mode on a partially installed unit or one with disconnected hoses.

Related Bosch Dishwasher Error Codes

Code: SA NLBosch SA NL Code: What Service Appliance No Light Means Code: E92Bosch E92 Error: Control Board Communication Fix Code: HUBBosch Dishwasher Error Codes: Complete List Code: HUBHow to Reset a Bosch Dishwasher

Same Fix Works on These Brands

Bosch shares the same hardware platform with these brands. The diagnosis and repair steps are identical.

Bosch dishwasherBosch Dishwasher E15: Fix the Anti-Flood Alert Fast Bosch dishwasherBosch Dishwasher Error Codes: Complete List + Fixes Bosch dishwasherHow to Reset a Bosch Dishwasher (Every Method)Bosch dishwasherBosch E24 Error: Drain Problem Solved Step by Step Bosch dishwasherBosch E25 Code: Drain Pump Fix Without a Technician Bosch dishwasherBosch Dishwasher Not Draining: Every Cause Covered

Models Known to Experience DIAG Errors

This repair applies to most Bosch dishwashers with this error code. Common model numbers include:

SHPM88Z75N, SHPM88Z55N, SHPK7ZL55N, SHE3AR75UC, SHEM63W55N, SHPM65Z55N, SHE3AR72UC, SHDF78Z55N, SHEM78ZH5N, SHPM98Z75N

Last verified for technical accuracy on March 14, 2026