EFI SYSTEM-BOSCH
84
24 690 01 Rev. KKohlerEngines.com
Code 22
Component: Throttle Position Sensor (TPS)
Fault: Unrecognizable signal is being sent from
sensor (too high, too low, inconsistent).
Condition: A “limp-home” operating mode occurs,
with an overall decrease in operating
performance and effi ciency. Fuel delivery
is based upon oxygen sensor and fi ve
mapped values only. Rich running
(black smoke) will occur until “closed
loop”operation is initiated. A stumble or
misfi re on hard acceleration and/or erratic
operation may be exhibited.
Conclusion: TPS Sensor Related
● Sensor connector or wiring.
● Sensor output affected or disrupted by
dirt, grease, oil, wear, or breather tube
position (must be to side opposite
TPS).
● Sensor loose on throttle body manifold.
Throttle Body Related
● Throttle shaft or bearings worn/
damaged.
Engine Wiring Harness Related
“35 Pin” (MA 1.7) Metal-Cased ECU:
● Pin circuits 12, 25 and/or 27 damaged
(wiring or connectors).
● Pin circuits 12, 25 and/or 27 routed
near noisy electrical signal (coils,
alternator).
● Intermittent 5 volt source from ECU
(pin circuit 25).
Engine Wiring Harness Related
“24 Pin” (MSE 1.0) Plastic-Cased ECU:
● Pin circuits 4, 8, and/or 14 damaged
(wiring, connectors).
● Pin circuits 4, 8, and/or 14 routed near
noisy electrical signal (coils, alternator).
● Intermittent 5 volt source from ECU
(pin circuit 14).
Engine Wiring Harness Related
“32 Pin” (MSE 1.1) Plastic-Cased ECU:
● Pin circuits 4, 8, and/or 18 damaged
(wiring, connectors).
● Pin circuits 4, 8, and/or 18 routed near
noisy electrical signal (coils, alternator).
● Intermittent 5 volt source from ECU
(pin circuit 18).
ECU/Harness Related
● ECU-to-harness connection problem.
Code 23
Component: ECU
Fault: ECU is unable to recognize or process
signals from its memory.
Condition: Engine will not run.
Conclusion: ECU (internal memory problem).
● Diagnosable only through elimination
of all other system/component faults.
Code 24 (Will not blink out)
Component: Engine Speed Sensor
Fault: No tooth signal from speed sensor. MIL
light will not go out when cranking.
Condition: None-engine will not start or run as ECU
is unable to estimate speed.
Conclusion: Engine Speed Sensor Related
● Sensor connector or wiring.
● Sensor loose or air gap incorrect.
Speed Sensor Wheel Related
● Damaged teeth.
● Gap section not registering.
Engine Wiring Harness Related
● Pin circuit wiring or connectors.
Pin(s) 3 and/or 21 for “35 Pin” (MA 1.7)
Metal-Cased ECU.
Pin(s) 9 and/or 10 for “24 Pin” (MSE
1.0) Plastic-Cased ECU.
Pin(s) 9 and/or 10 for “32 Pin” (MSE
1.1) Plastic-Cased ECU.
ECU/Harness Related
● ECU-to-harness connection problem.
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