Kohler 5ECD Service Manual page 30

SECM Fault Codes and Diagnostics (Continued)
Fault
Code
Displayed Description
EC43* Electronic Spark Trigger
(EST) 2 High
EC46 Injector Input is Low
LOP Low Oil Pressure
EC48 Electronic Throttle Control
(ETC) Spring Test Failed
EC49 Manifold Air Pressure
(MAP) Sensor Input High
EC50 Manifold Air Pressure
(MAP) Sensor Input Low
EC51 Electronic Throttle Control
(ETC) Driver Fault
HB* Battery Voltage Sensor
Input High
LB* Battery Voltage Sensor
Input Low
EC54 Transducer Voltage (XDRP)
Sensor Input High
* Indicates a stored fault code.
30 Section 4 Controller
Check
The Electronic Spark Trigger is a current driver signal and this fault appears if the signal from
the SECM is open or lost or the coil driver signal is high or overcurrent.
Check the coil driver wiring for an open circuit or disconnected connector:
SECM Pin 7 (EST 1) to COIL Pin A
Verify GND on COIl Pin B
Verify GND on COIL Pin C
Verify GND on COIL Pin D
Verify +12VDC on COIL Pin E
To check the internal circuit, disconnect the coil connector and measure the resistance from pin
to pin. See Figure 5-20.
Fault appears when the power to the injector is low.
Fault appears when the oil pressure switch is opened or disconnected, normally indicating a
low oil condition. See Figure 4-5.
Upon initial engine startup, the SECM performs a safety test of the throttle return spring. If this
spring has become weak, the throttle will fail this test and set the fault. Perform a throttle spring
test by cycling the ignition and rechecking for the fault.
NOTE: Do not service the throttle components. Repair or replace the throttle body assembly.
The manifold air pressure sensor fault appears if the TMAP pressure signal wire is shorted to
power, shorted to the IAT signal, the TMAP has failed, or the SECM has failed. Check the
TMAP connector and MAP signal wiring for a shorted circuit:
TMAP Pin 4 to SECM Pin 5 (SIGNAL)
TMAP Pin 1 to SECM Pin 1 (GND)
TMAP Pin 3 to SECM Pin 18 (XDCR +5VDC)
Check the MAP sensor by disconnecting the TMAP connector and measuring at the sensor:
TMAP Pin 1 (GND) to Pin 4 (PRESSURE SIGNAL KPA) of 2.4 kOhms -- 8.2 kOhms
TMAP Pin 3 (PWR) to Pin 4 (PRESSURE SIGNAL KPA) of 3.4 kOhms -- 8.2 kOhms
The manifold air pressure sensor fault appears if the TMAP pressure signal wire is
disconnected or the circuit is opened to the SECM. (EC50 and EC56 are expected faults when
the TMAP connector is unplugged). Check the TMAP connector and MAP signal wiring for an
open circuit:
TMAP Pin 4 to SECM Pin 5 (SIGNAL)
TMAP Pin 1 to SECM Pin 1 (GND)
TMAP Pin 3 to SECM Pin 18 (XDCR +5VDC)
Check the MAP sensor by disconnecting the TMAP connector and measuring at the sensor:
TMAP Pin 1 (GND) to Pin 4 (PRESSURE SIGNAL KPA) of 2.4 kOhms -- 8.2 kOhms
TMAP PIn 3 (PWR) to Pin 4 (PRESSURE SIGNAL KPA) of 3.4 kOhms -- 8.2 kOhms
Fault appears if an overcurrent condition occurs on either the ETC+ or ETC-- driver signals.
Check the ETC driver wiring for a shorted circuit:
ETC+ Pin 1 to SECM Pin 22
ETC-- Pin 4 to SECM Pin 24
Check the ETC internal motor drive by disconnecting the throttle connector and measuring the
motor drive resistance at the throttle:
TPS Pin 1 (+DRIVER) to Pin 4 (--DRIVER) approx. 3.0 Ohms ¦ 30 %.
Fault appears if the power to the SECM increases above 15.9 VDC. See Figure 4-6.
Check the battery and charging system voltage:
Check the battery voltage during starting and with the engine running.
Check the voltage regulator, alternator, and charging system.
Check the battery and wiring for overheating and damage.
Measure the battery power at the SECM with a multimeter:
SECM Pin 13 (BATT+) to SECM Pin 14 (BATT--)
Fault appears if the power to the SECM drops below 9.5 VDC. See Figure 4-6.
Check the battery voltage:
Perform a maintenance check on the electrical connections to the battery and ground.
Check the battery voltage during starting and with the engine running to verify charging
system and alternator function.
Measure the battery power at the SECM with a multimeter:
SECM Pin 13 (BATT+) to SECM Pin 14 (BATT--)
Fault appears if the sensor power from the SECM increases above 5.9 VDC.
Measure the transducer power at the TMAP connector with a multimeter:
TMAP Pin 3 +5VDC to TMAP Pin 1 XDCR GND
Verify transducer power at the SECM with a multimeter:
SECM Pin 18 +5VDC to SECM Pin 1 XDCR GND
Verify transducer power at ETC with a multimeter:
ETC Pin 3 XDCR PWR to ETC Pin 2 XDCR GND
TP-6391 9/08