Diagnostic Tips - Buell 2008 XB SERIES Electrical Diagnostics Manual

DTC P0117 (14), P0118 (14)
GENERAL
Engine Temperature (ET) Sensor
Do not pull on ET sensor wiring. Excess strain to sensor wiring
will cause sensor damage.
See Figure 2-47.The Electronic Control Module (ECM) supplies
and monitors a 0-5 volt signal to one side of the ET sensor.
The other side of the ET sensor is connected to ground through
the engine.
Refer to Table 2-31. The ET sensor is a thermistor device which
means that at a specific temperature, it will have a specific
resistance across its terminals. As this resistance varies, so
does the voltage sent to the temperature sensor input on the
ECM.
At high temperatures, the resistance of the sensor is very
low. This effectively lowers the signal voltage.
At low temperatures, the resistance is very high, allowing
the voltage to rise close to the supplied voltage of 5 volts.
The ECM monitors this voltage to compensate for various
operating conditions.
Table 2-30. Code Description
DTC CHECK
ENGINE
LAMP CODE
P0117 14
P0118 14
ed01473
Figure 2-47. Location of Engine Temperature Sensor in
Rear Cylinder Head
2-58 2008 Buell XB Diagnostics: Engine Management
NOTE
DESCRIPTION
Engine sensor voltage low
Engine voltage high/open
Table 2-31. Engine Temperature Sensor Specifications
VOLTS RESISTANCE
0.00 0
0.21 145
0.42 303
0.62 463
0.81 638
1.20 1042
1.59 1539
3.01 4991
4.43 25,647
4.63 41,295
4.83 93,759
4.88 134,200
4.93 232,414
All voltage and resistance values are approximate (±20%).
DIAGNOSTICS
PART NUMBER
B-48115 BREAKOUT BOX
HD-41404-B HARNESS CONNECTOR TEST KIT

Diagnostic Tips

An intermittent may be caused by a poor connection, rubbed
through wire insulation or a wire broken inside the insulation.
Check for the following conditions:
Poor Connection: Inspect ECM harness connector [11]
for backed out terminals, improper mating, broken locks
improperly formed or damaged terminals, poor terminal-
to-wire connection and damaged harness.
Shifted Sensor: The temperature-to-resistance values
table may be used to test the ET sensor at various temper-
ature levels in order to evaluate the possibility of a shifted
(out-of-calibration) sensor which may result in driveability
problems.
Diagnostic Notes
Each reference number below correlates to a circled number
on the flow chart(s).
1. Connect BREAKOUT BOX (Part No. B-48115) to ECM.
See 2.6 BREAKOUT BOX.
2. Use HARNESS CONNECTOR TEST KIT (Part No. HD-
41404-B), purple socket probes and patch cord.
2.18
TEMP °C TEMP °F
300 572
255 491
210 410
190 374
170 338
150 302
130 266
85 185
40 104
25 77
10 50
0 32
-10 14
NOTE
TOOL NAME