Preparation for Test (DTC readout): 1. Fuses OK. 2. Ignition: ON 3. Connect Hand-Held Tester (HHT) according to connection diagram shown in section 0. 4. Voltage supply to control modules and CAN data lines ok, see 23, 5. All CAN data lines must be connected. The diagnostic trouble codes (DTC's) can only be read out and erased using the Hand-Held Tester (HHT). DTCs for the system being checked may be located in other control modules, therefore it is important to check the DTC memory on all control modules that are relevant to the system being checked. While performing the DTC readout, it is possible that DTCs may appear that are not relevent to the system being checked, meaning that all stored DTCs in that particular control module are being displayed. Non-relevant DTCs are described in each system as necessary. Note regarding Diagnostic Trouble Codes (DTC's): Current diagnostic trouble codes are highlighted in black on the display. Additional detailed fault information based on fault type is displayed with nearly all diagnostic codes (DTC's) such as: > Resistance too great < Resistance too low - Short circuit to ground (GND) + Short circuit to positive (POS) -//- Open circuit Fault frequency Faults are noted by frequency of occurrence, i.e.: 4 periodic faults, 4 occurances.

Conventional tools, test equipment

Description	Brand, model, etc.
Multimeter 1)	Fluke models 23, 83, 85, 87, 88

1) Available through the MBUSA Standard Equipment Program.

DTC		Possible cause	Test step/Remedy 1)
		Electronic ignition lock control module (N73)	Replace N73
		Roof control panel control module (N70)	Replace N70
		Signal pick-up and activation module (SAM) (N10/1)	Replace N10/1
		Low voltage	23 1.0 - 11.0
		Excessive voltage	23 1.0 - 11.0
		CAN: communication fault between electronic ignition lock control module (N73) and Roof control panel control module (N70)	23 54.0-62.0, 64.0, 67.0, 89.0-96.0
		CAN: communication fault between electronic ignition lock control module (N73) and Signal pick-up and activation module (SAM) (N10/1)	23 89.0-96.0
		HCS switch (S4/1), signal > 25 seconds	23 122.0
		Tailgate window wiper switch (S6/1s4), signal > 25 seconds	23 121.0
		Rain sensor (B38), no communication	23 112.0-114.0
		Rain sensor (B38) faulty	Replace B38
		Rain sensor (B38) not adapted to windshield (IR beam functional problems)	Clean windshield, Replace wiper blade insert, B38, Replace optical unit of B38, replace windshield.
		Excessive windshield surface temperature	Windshield temperature > 65° C (148° F), replace B38
		Sporatic faults	if often, replace B38
		Wiper system operation not synchronised	Erase DTC memory, Operate windshield wiper through 40 cycles.
		Activation of windshield washer relay (K40/2k3) +, - (tailgate)	23 116.0-118.0
		Activation of windshield washer relay (K40/2k3) - (windshield)	23 109.0
		Rain sensor (B38) no communication	23 113.0-115.0
		PSE control module (A37), combined functions	Replace A37
		Roof control panel control module (N70)	Replace N70
		Low voltage	23 1.0 - 11.0
		Excessive voltage	23 1.0 - 11.0
		Dome lamp switch on/off (N70s4), signal > 25 seconds,	See 13
		Work lamp switch on/off (N70s5), signal > 25 seconds, Model 208.4 only: Left front work lamp switch on/off (N70s6), signal > 25 seconds, Right front work lamp switch on/off (N70s7), signal > 25 seconds,	See 13
		Door switch on/off (N70s3), signal > 25 seconds,	See 13
		Rear dome lamp switch on/off (N70s2), signal > 25 seconds,	See 13
		Voltage supply for left and right vanity mirror,	Wiring, Replace N70
		Entrance/exit lamps (E17)	23 130.0 23 131.0
		Signal pick-up and activation module (SAM) (N10/1)	Replace N10/1
		Low voltage	23 1.0 - 11.0
		Excessive voltage	23 1.0 - 11.0
		Heated rear window switch, signal > 25 seconds, +	23 133.0
		PSE control module (A37), combined functions	Replace A37

1) Observe Preparation for Test, see 22.