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1F1 -- 86 M162 ENGINE CONTROLS
D AEW OO M Y_2000
ENGINE CONTROL MODULE
YAA1F830
The Engine Control Module (ECM), located inside the right side kick panel, is the control center of the fuel injection
system. It constantly looks at the information from various sensors and controls the systems that affect the vehicle’s
performance. Engine rpm and air mass are used to measure the air intake quantity resulting in fuel injection metering.
The ECM also performs the diagnostic functions of the system. It can recognize operational problems, store failure
code(s) which identify the problem areas to aid the technician in making repairs.
There are no serviceable parts in the ECM. The calibrations are stored in the ECM in the Programmable Read Only
Memory (PROM).
The ECM supplies either 5 or 12 volts to power the sensors or switches. This is done through resistance in the ECM
which are so high in value that a test light will not come ON when connected to the circuit. In some cases, even an
ordinary shop voltmeter will not give and accurate reading because its resistance is too low. You must use a digital
voltmeter with a 10 Mohm input impedance to get accurate voltage readings. The ECM controls output circuits such as
the ignition coils, the fuel injectors, the fuel pump relay, the intake manifold resonance flap, the camshaft actuator, the
canister purge valve, etc., by controlling the ground circuit.
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SERIAL DATA COMMUNICATION
KAB1F350
Failure
CodeDescriptionTrouble AreaMaintenance Hint
23CAN communication
failure: ASR/MSR
When CAN signal message
missing or implausibility for
ASR/MSR unit or not
initialized condition
DInspection the ASR unit with CAN
connection
DInspection the Engine Control Module
(ECM) pin 38, 37 about short circuit or
open with bad contact
DInspection the ECM
24CAN communication
failure: ABS
When CAN signal message
missing or implausibility for
ABS unit or not initialized
conditionDInspection the ABS unit with CAN
connection
DInspection the ECM pin 38, 37 about
short circuit or open with bad contact
DInspection the ECM
26CAN communication
failure: TCU (A/T only)
When CAN signal message
missing or implausibility for
TCU unit or not initialized
conditionDInspection the TCM unit with CAN
connection
DInspection the ECM pin 38, 37 about
short circuit or open with bad contact
DInspection the ECM
27
CAN communication
failure: TOD
(E32 only)When CAN signal message
missing or implausibility for
TOD unit or not initialized
conditionDInspection the TOD unit with CAN
connection
DInspection the ECM pin 38, 37 about
short circuit or open with bad contact
DInspection the ECM
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Failure
CodeDescriptionTrouble AreaMaintenance Hint
29
CAN communication
failure: ID 200h not
plausibleWhen CAN signal message
missing or implausibility for
ABS/ABD unit or not
initialized conditionDInspection the ABS/ABD unit with
CAN connection
DInspection the ECM pin 38, 37 about
short circuit or open with bad contact
DInspection the ECM
30
CAN communication
failure: ID 208h not
plausibleWhen CAN signal message
missing or implausibility for
ABS/ABD unit or not
initialized conditionDInspection the ABS/ABD unit with
CAN connection
DInspection the ECM pin 38, 37 about
short circuit or open with bad contact
DInspection the ECM
31
CAN communication
failure: communication
initialization failure
When CAN signal message
missing or implausibility for
each unit (ABS, ASR, TCM,
TOD etc.) or not initialized
conditionDInspection the each control unit with
CAN connection
DInspection the ECM pin 38, 37 about
short circuit or open with bad contact
DInspection the ECM
59
CAN communication
failure: MSR data
transmission not
plausibleWhen CAN signal message
missing or implausibility for
MSR unit or not initialized
condition
DInspection the MSR unit with CAN
connection
DInspection the Engine Control Module
(ECM) pin 38, 37 about short circuit or
open with bad contact
DInspection the ECM
60
CAN communication
failure: ASR data
transmission not
plausibleWhen CAN signal message
missing or implausibility for
ASR unit or not initialized
condition
DInspection the ASR unit with CAN
connection
DInspection the Engine Control Module
(ECM) pin 38, 37 about short circuit or
open with bad contact
DInspection the ECM
Circuit Description
The provision for communicating with the ECM is the Data Link Connector (DLC). It is located in the instrument panel
fuse block. The DLC is used to connect the scan tool. Battery power and ground is supplied for the scan tool through
the DLC. CAN line is used to communicate with the other module such as the Transmission Control Module (TCM) and
Transfer Case Control Unit (TCCU).
Keyword 2000 Serial Data Communications
Each bit of information can have one of two lengths: long or short. This allows vehicle wiring to be reduced by transmit-
ting and receiving multiple signals over a singles wire. The message carried on KWP 2000 data streams are also priori-
tized. If two messages attempt to establish communications on the data line at the same time, only the message with
higher prioritywill must wait.
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1F1 -- 90 M162 ENGINE CONTROLS
D AEW OO M Y_2000
INTERNAL FAILURE
Failure
CodeDescriptionTrouble AreaMaintenance Hint
21Transmission coding
failureWhen faulty of variant coding
of transmission
DInspection the coding condition
through scan tool
DInspection the Engine Control Module
(ECM)
DInspection the CAN line
DInspection the TCM
136ECM failure (RAM)
When malfunction of random
access memory -- ECM
internal error
DInspection the ECM
142Uncoded/ unprogramed
ECMWhen malfunction of ECM
coding-- required ECM
encoding
DFulfill the ECM variant coding
137ECM failure (EPROM)
143
ECM failure
(EEPROM/Flash -- EPPOM
checksum failure)
144ECM failure (coding ID
checksum failure)When malfunction of ECM
internalDInspection the ECM
145ECM failure (coding
checksum failure)
146ECM failure (programming
checksum failure)
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ELECTRONIC THROTTLE CONTROLLER SAFETY MALFUNCTION
Failure
CodeDescriptionTrouble AreaMaintenance Hint
110Throttle actuator
learning data fault
117Exceed fuel-- cut safety
time
120
Cruise control
interruption memory
failure
138Call Monitoring
139
Servo motor control
output interruption
memory failure
140Servo motor open/short
186ECM failure
(incompatible CPU)
187ECM failure (CPUs
communication failure)
188ECM failure (CPU 2
configuration failure)
189ECM failure (CPU 2
fault)
190
ECM failure (CPU run
time failure between
CPUs)System internal failureDInspection the Engine Control Module
(ECM)
231
ECM failure (CPU 2
cruise control message
counter failure)
232Over deceleration limit
(CPU 2)
233Over acceleration limit
(CPU 2)
234Cruise control lever dual
operation (CPU 2)
235
Cruise control lever
safety terminal failure
(CPU 2)
236Unusual pedal position
variation (CPU 2)
237Unusual throttle position
variation (CPU 2)
238
Unusual throttle
controller monitoring
data comparison fault
(CPU 2)
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M162 ENGINE CONTROLS 1F1 -- 93
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Failure
CodeDescriptionTrouble AreaMaintenance Hint
239
Unusual accelerator
pedal position sensor
comparison fault
(CPU 2)
240
Throttle potentiometer
comparison fault
(CPU 2)
241Unusual CPU
communication (CPU 2)
242Unusual CPU
configuration (CPU 2)
243A/D converter failure
(CPU 2)
244
Accelerator pedal
position sensor setpoint
fault between CPU 1
and CPU 2
System internal failureDInspection the Engine Control Module
(ECM)
245
Position controller
setpoint fault between
CPU 1 and CPU 2
y(ECM)
246
MSR setpoint fault
between CPU 1 and
CPU 2
247
Idle control setpoint fault
between CPU 1 and
CPU 2
248A/D converter overflow
(CPU 2)
249ROM fault (CPU 2)
250RAM fault (CPU 2)
251Cycle monitor fault
(CPU 2)