1993 BMW 318is AutomaticFACTORY OEM SERVICE PROCEDURE

Trouble Code Definition

318i & 318is (DME 1.7) FAULT CODE IDENTIFICATION

Fault Codes Affected Circuit Probable Cause
1 Fuel Pump Relay (1) Shorted Relay Or Circuit To DME Control Unit Pin No. 1
3 Fuel Injectors (No. 1 & 3) (2) Shorted/Open Circuit In Fuel Injectors Or Their Circuit Wiring
8 CHECK ENGINE Light Shorted Circuit On Indicator Light Or Its Circuit Wiring
12 Throttle Potentiometer (TPS) Shorted/OpenCircuit In Sensor Or Its Circuit Wiring
16 Camshaft Sensor Faulty Signals From Camshaft Sensor At 2500 RPM
29 Idle Speed Control Shorted Circuit In Wiring To DME Control Unit Pin No. 29
32 Fuel Injectors (No. 2 & 4) Shorted/Open Circuit In Fuel Injectors Or Their Circuit Wiring
36 Fuel Tank Venting Valve Shorted/Open Circuit On Fuel Tank Venting Valve Or Its Circuit Wiring
37 Oxygen Sensor Heater Relay Shorted/Open Relay Or Circuit To DME Control Unit Pin No. 37
41 Airflow Sensor Shorted/Open Circuit On Airflow Sensor Or Its Circuit Wiring Or Sensor Out Of Range
54 DME Power Supply (3) Voltage To DME Control Unit Drops To Less Than 9 Volts Or Exceeds 16 Volts
70 Oxygen Sensor (4) Shorted/Open Circuit On Oxygen Sensor Or Its Circuit Wiring
73 Speed Sensor (Signal) (5) Faulty Speed Sensor Input Signal
77 Intake Air Temp. Sensor (6) Shorted/Open Circuit On Sensor Or Its Circuit Wiring
78 Engine (Coolant) Temp. Sensor Shorted/Open Circuit On Engine Temperature Sensor Or Its Circuit Wiring
85 A/C Compressor (7) Open Circuit On Pin No. 86 And Short To Battery On Pin No. 85
100 Final Stage (Output Signal) Loose Connection On Final Stage Output Signal
200 DME Control Unit Faulty DME Control Unit Memory Modules
201 Oxygen Sensor Control Rich Or Lean Air/Fuel Mixture For At Least 8 Seconds
(1) Fault is recognized only when at least one additional final stage (output signal) is faulty.
(2) Injector group is deactivated with a short circuit in either injector or its power supply wiring. Cylinders No. 2 and 4 remain in operation.
(3) Check connections and wiring harness for resistance, incorrect alternator belt tension and defective alternator or voltage regulator.
(4) Engine coolant temperature must be at least 158°F (70°C) and an engine load signal must be 4.5 milliseconds for at least 5 seconds.
(5) Fault is set when engine speed is 4500 RPM, engine load signal is 4.0 milliseconds and vehicle speed is 3-5 MPH.
(6) Recognition of an open circuit requires at least 3 minutes time after starting engine and an idle speed for 30 seconds (minimum).
(7) Fault is set when DME control unit simultaneously receives battery voltage on pin No. 85 and zero volts on pin No. 86.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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