Troubleshooting D-Jetronik

1.Engine will not start, K-pump is not running.

Swap check and restore voltage to pump, if necessary. Pump. ECU defekt.


1: To observe the display better, it is advisable to rotate the crankshaft by hand. Due to the inertia of some devices, it is not always possible to measure accurately. One can help but by pin 12 sets the control module connector at 11,
a diode test lamp does and this connects to pin 16 and to pin 21 or pin 22.
Upon startup, the diode will then flash, or commute the display.
2: accelerator pass through slowly. The display is 10x commute between 0
and OL. When you release the value in OL remains. If not, the switch is faulty.
3: throttle in idle = 0 ohms, with deflection greater than 1 ° (about 0.4-0.5mm) = OL
4: In case of parallel valves pull the other plug to measure only one valve may or share the setpoint for a valve by the number of connected valves.
OL means Open line or infinite OHM.
Notes: The two temperature sensors are NTC. This means that their resistance decreases with increasing heat. The value of the cooling water temperature sensor at operating
Therefore temperature is about 300-500 ohms. For measurements on this component, it is useful to have a comparison value only at the sensor and then to measure the control unit connector and can track resistances. (Measurement at the component with the plug disconnected!)


Oldtimer-Steuergeräte - Peter Hemmersbach repariert defekte D-Jetronik Steuergeräte
Peter Hemmersbach repairs defective D-Jetronik control units in his workshop.
Oldtimer-Steuergeräte - alter Mercedes
The D-Jetronik injection was real "high-tech" in the late 60s and it took over the place of mechanically controlled injection systems in many top models.
Oldtimer-Steuergeräte - gepflegte Oldtimer sind auch heute zuverlässige Fahrzeuge
A classic car can even today be a very reliable vehicle. It is important to take good care of the technique and to have a little interest in the topic.


We repair D-jetronik control units
also lucas ecu´s, ignition control modules and fuel pump relays from your Vintage Car.


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