Bosch E09 means the heating system failed to reach target temperature. Most Bosch models use a flow-through heater (not an exposed element) - test it with a multimeter before ordering: 20-30 ohms is good, open circuit means it is burned out. Test the NTC temperature sensor first (should read 10,000-12,000 ohms at room temp) since it costs under $25 vs $80-120 for the heater.
I've been fixing Bosch dishwashers for fifteen years and E09 is probably the repair I see most. The flow-through heater sits under the wash sump and just quietly dies on you, and you don't even know until your dishes come out cold and greasy. Good news is the part's around $40-80, and if you know where the four mounting clips are, you're done in under an hour.
OK so here's the thing about Bosch dishwashers from 2010 onward. They don't use a coil element on the tub floor anymore. They've got a flow-through heater mounted outside the tub that heats water as it circulates. You can't even see it from inside. And sometimes it's not the heater at all. A bad NTC temp sensor throws E09 too, and that sensor's like $15-25, so test it before you buy the $100 heater.
Most Likely Causes
Based on aggregated repair data, here is the probability breakdown for this error code:
Failed flow-through heater element40%
Failed NTC temperature sensor giving false cold reading24%
Wiring harness break between heater and control board14%
E09 shows up on the display partway through a wash cycle or right at the start of the heated dry phase
Dishes come out cold to the touch after a full cycle, with visible food residue still on plates and glasses
There's a cloudy white film all over your glasses even with rinse aid loaded in the dispenser
The whole cycle runs fine but everything's still dripping wet when you open the door
The detergent pod didn't dissolve, there's a gunky chunk of it sitting in the bottom of the tub
Can you reset a Bosch dishwasher to clear the E09 code?
E09 won't clear with a simple reset if the heater or NTC actually failed. After you replace the part, hold the Start/Reset button for about 5 seconds. The display will flash and then go dark. Wait another 30 seconds before starting a new cycle. That clears the stored fault code from the control board. If E09 comes back on the very next cycle, something's still wrong and you've got more diagnosing to do.
Tools Required for Diagnosis
Phillips #2 screwdriverTorx T20 screwdriverAdjustable wrench or 5/16 socketMultimeter with resistance (ohms) functionElectrical contact cleaner spraySmall wire brush or old toothbrushNon-contact voltage testerFlashlight or headlampOld towels for water spillage when pulling the unit out
Diagnostic Checklist
Follow these steps in order. We start with the easiest external fixes before opening up the machine.
ComponentComponent Under Test
Expected Range20–30 ohms
ConditionIf Open (OL) or infinite, replace component.
Replacement Parts
If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.
Part Name
OEM Number
Estimated Price
Flow-Through Heater Assembly00674541 · $85–$160
00674541
$85 – $160
NTC Temperature Sensor00165258 · $15–$30
00165258
$15 – $30
Frequently Asked Questions
Can I still run my Bosch dishwasher with E09?
Technically yeah, it'll run through a cycle. But here's the problem. Cold water doesn't actually clean dishes, it just moves grease and bacteria around. You'll still have food residue, detergent film, and germs on your plates when you're done. It's especially not great if you're washing baby bottles, sippy cups, or cutting boards where sanitation actually matters. Honestly, just stop using it until it's fixed. The dishes you run in the meantime aren't actually getting clean anyway, so you're wasting water and detergent on every cycle.
How much does a Bosch flow-through heater replacement cost?
The OEM heater assembly, part number 00674541, runs about $85-160 depending on where you order it. Third-party compatible parts are closer to $40-80 and they're generally fine. If you hire a tech, add $150-300 in labor, so total repair is $235-460. Here's how I'd think about it. A new entry-level Bosch starts around $400-500. If your unit's under 8 years old and hasn't had other major issues, fix it. Over 10 years old with a bunch of repairs already done on it? I'd honestly start shopping for a replacement instead.
Does E09 affect drying performance?
Yes, a lot actually. Bosch's drying system relies on residual heat from the hot wash water, not a separate drying element like some other brands use. No hot wash water means no residual heat means wet dishes every time. On the 500 and 800 series with AutoAir or CrystalDry, you'll get some help from the ventilation system or zeolite minerals, but it won't be anywhere close to normal. Wet dishes are actually one of the first signs people notice before they even see the E09 code. Way wetter than usual is a warning sign worth paying attention to.
How do I test the Bosch heater with a multimeter?
Shut power off at the breaker, not just the cancel button. Pull the dishwasher out and find the flow-through heater underneath. It's the cylindrical assembly bolted to the bottom of the sump. Disconnect both electrical connectors from the heater. Set your multimeter to resistance (ohms) mode. Touch the probes to the two terminals on the heater. A working heater reads 20-30 ohms. If you get OL or infinity, the element inside burned through and the heater's done. There's no fixing the element itself. The whole heater assembly has to be replaced, you can't repair it in the field.
Is E09 the same as H01 on a Bosch dishwasher?
Nope, different problems entirely. E09 means the heater completely failed, zero heat output. H01 is a heating timeout code, meaning the heater's working but couldn't get the water hot enough fast enough. H01 is usually just cold water sitting in the supply line before you started the cycle. Run your hot water tap for a full minute before starting the dishwasher and H01 will often just go away on its own. E09 won't. If E09's showing up, the heater itself is burned out or the NTC sensor is lying to the board. No amount of preheating the supply line fixes that.