Generac Power Systems GP Series Diagnostic Repair Manual page 54

Section 5 Engine Diagnostic Tests
b. If the harness connector for the cylinder head
temperature sensor appears compromised or
damaged, replace the wire harness.
See Figure 5-91.
2.
Temperature Sensor and the 48-pin ECM harness
connector at the ECM. Probe the YE terminals at
the sensor connector and at the ECM harness
connector.
Figure 5-91. ECM Harness Connector
Pin Wire Color
9 Yellow/Green
12 Yellow
Probe the GN/YE terminal at the sensor and at the
3.
GN/YE terminal at the ECM harness connector.
Also, check each wire (YE and GN/YE) to ground.
Refer to the Pin-Out of the ECM harness
connector.
a. The resistance of each wire should be less
than 0.3 ohms.
b. If the resistance of a wire is greater than 0.3
ohms, or if a wire is open (OL), or if a wire is
shorted to ground, replace the wire harness.
c. If the resistance is good, go to Step 4.
See Figure 5-92. Disconnect the cylinder head
4.
temperature sensor. Measure the resistance of the
sensor between the YE terminal and the GN/YE
terminal, and measure the resistance of the sensor
pins to ground.
Figure 5-92. Engine Head Temperature Sensor (EHT)
Connector
a. Compare the resistance value to
not within the specification, replace the sensor.
b. If no other faults are found, replace the ECM.
48
Disconnect the Cylinder Head
Function
Battery – (GND)
Warning Lamp
Table
Table 5-5. Engine Head Temperature Sensor (EHT)
YE to GN/YE Terminals
YE Terminal to Ground
GN/YE Terminal to Ground
Test 28 – Carbon Monoxide (CO)
Module Verification Test
Purpose
To determine if the CO module is installed correctly and
functioning properly
015043
replacement or repair. The status of the module is
determined by LED patterns and colors.
Procedure
NOTE: Do not install CO badging (decal) prior to
performing this test
NOTE: The generator must run under normal operation
with no CO module notifications for a minimum of 65
seconds before performing the pin test.
See Figure
1.
insert a small rod into test switch hole (A).
NOTE: Use an Allen wrench or the blunt end of a drill bit
with a maximum diameter of 3/64".
Depress and hold the test switch until notification
2.
LEDs appear and generator shuts off.
NOTE: The LED pattern for a successful pin test is both
lights on solid (not blinking) as shown in
IMPORTANT NOTE: Do NOT insert the pin tool into the
LED holes (B) located above and below the test switch
access hole. Damage the LEDs will occur.
A
B
015044
Figure 5-93. CO Module Test Switch and LEDs
5-5. If
Resistance
approx. 14.5 Ohms
@ambient temp
OL - Open Circuit
OL - Open Circuit
on a generator
5-93. With the generator running,
Table
B
Diagnostic Repair Manual
unit after
5-6.
015045