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.

When I get called out to a Bosch job, diagnostic mode is the first thing I run. Takes 12-15 minutes and tells you exactly which component failed instead of you guessing and throwing parts at it blind. That gets expensive fast. Run it after repairs too, to confirm the fix actually worked before you close everything back up.

BoschDishwasherSeverity: lowDifficulty: intermediate

Time to Fix

15–90 min

Difficulty

intermediate

Parts Cost

$0 (no parts needed)

Tools Needed

Pen and paper to write down fault codes as they appear on the display, Phone or camera to photograph the display showing fault codes as a backup

How to Enter Bosch Dishwasher Diagnostic Mode

OK so here's the deal. Bosch diagnostic mode isn't a reset trick or a soft reboot. The control board actually activates each component one at a time, watches the response, and logs pass or fail. You get specific component data in 15 minutes instead of running a full 2-hour cycle and hoping something breaks. Honestly it's one of the better built-in diagnostic systems I've seen from any major appliance brand.

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%

Symptoms You May Notice

Dishwasher cancels mid-cycle and throws a code that shows up once, then disappears before you can chase it down
Machine fills with water but won't start washing, or starts washing just fine but never drains
Runs fine sometimes, then randomly stops with E codes you can't reproduce consistently during a normal cycle
You replaced a part and want to actually confirm it fixed the problem before putting everything back together
Display shows something weird like all dashes or flashing LEDs with no clear readable code

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

To exit early, press and hold the Start/Reset button for 3-5 seconds. The machine drains whatever water filled during testing and goes back to standby. Some models use a Cancel button instead, same thing. If the buttons aren't responding at all, cut the breaker for 30 seconds and that'll force an exit. After the cycle finishes normally it exits automatically on its own.

Tools Required for Diagnosis

Pen and paper to write down fault codes as they appear on the displayPhone or camera to photograph the display showing fault codes as a backupFlashlight to read the model number label inside the door frame if it's faded

Diagnostic Checklist

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

Did the fix not work?

If the problem comes back after following these steps, a component has permanently failed and needs replacement. Check the specific error code your dishwasher is showing:

SA NL Error →E92 Error →HUB Error →HUB Error →

Frequently Asked Questions

What is the Bosch diagnostic mode button combination?

For 2015 and newer Bosch dishwashers, basically the 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 the lights will do something different. Close the door and the test starts automatically. For pre-2010 SHU and SHV models, you do a 3-button rotating sequence: press buttons 1, 2, and 3 in quick succession, then repeat within 4 seconds. The timing on those old boards is touchy, so go fast and don't pause between presses.

How do I read Bosch diagnostic codes?

Each component test shows a result on the display when it finishes. Zero means it passed. Anything else is an error code for that component, same codes the machine uses during normal error detection. E01 is the wash motor, E24 means something's wrong in the drain path, E15 is the float switch, and so on. Write every non-zero result down on paper, don't rely on memory. Some models only show the final stored fault code at the end rather than giving you a running score per test. Either way, zero is good, anything else needs attention.

What's the difference between diagnostic mode and regular error codes?

Regular error codes pop up on their own when the dishwasher hits a problem during a normal wash cycle. You didn't ask for them, the machine just throws them when something goes wrong. Diagnostic mode is something you actively trigger. It runs each component in a controlled sequence and records pass or fail for each one. The big advantage is with intermittent problems. If your dishwasher acts up sometimes but not every cycle, the error code can disappear before you catch it. Diagnostic mode can surface that fault even when the machine seems like it's working fine right now.

I'm stuck in diagnostic mode, how do I get out?

Hold Start/Reset for 3-5 seconds. That stops the test, drains whatever water filled during testing, and puts it back in standby. Some models use a Cancel button instead of Start/Reset, same deal. If the buttons aren't doing anything at all, your control board might have locked up. Go to your breaker box, cut the circuit for 30 seconds, flip it back on, and that'll force an exit. I've had to do that maybe twice in a couple hundred Bosch diagnostics, so it's pretty rare but it does happen.

Can I damage the dishwasher by running diagnostic mode?

No. It's running the same stuff a normal wash cycle does: fill, circulate, heat, drain. The only thing you need to make sure of is that the machine is fully installed with all the hoses connected before you start. Don't run diagnostics on a unit that's been pulled out for service unless the drain hose is in a bucket and the supply line is connected. Had a guy last month try to diagnose a unit he'd pulled out and left disconnected, ended up with water all over his kitchen floor. Totally avoidable.

How long does the Bosch diagnostic test cycle take?

Usually 10-15 minutes start to finish. Way faster than a normal wash cycle. The test hits water fill, circulation, heating, and drain in sequence but it doesn't heat to full temperature or run through a complete wash, it's just confirming each component responds and operates. If the diagnostic stops before finishing on its own, that itself tells you something. A wash motor that seizes mid-test or a drain pump that won't run will cut the sequence short and usually throw a code right at that point.

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 dishwasherHow to Reset a Bosch Dishwasher (Every Method)Bosch dishwasherBosch E09: Heating Element Not Working Bosch dishwasherBosch E17 Error: Too Much Water Coming In Bosch dishwasherBosch E11 Error: Temperature Sensor (NTC) Fault Bosch dishwasherBosch Dishwasher Troubleshooting: 15 Problems, Fixed Bosch dishwasherBosch E92 Error: Control Board Communication Fix

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

Written by

Mike Sullivan

Lead Appliance Repair Technician · 20 years experience

Last verified for technical accuracy on March 14, 2026