System Operation Description:
Use this procedure if the diagnostic code in Table 1 is active.
Conditions which Generate this
Code
261-13 Engine Timing
Calibration calibration
required
The Electronic Control Module
(ECM) detects a calibration offset
of zero for the engine
speed/timing sensor.
Default timing of zero
is used. Timing can be
off by 3 degrees.
The code is active.
The engine speed/timing sensor is calibrated with a two-step process. A new timing
reference is calculated first. The reference is based on the signals from the transducer
and the engine speed/timing sensor. Next, the new timing reference is programmed
into the permanent memory of the engine ECM.
The engine speed/timing sensor provides engine information to the ECM. The ECM
powers the engine speed/timing sensor with 12.5 ± 1.0 VDC. The sensor senses the
tooth pattern on the timing reference gear that is attached to the left camshaft. As the
timing gear rotates past the engine speed/timing sensor, a signal is generated in the
sensor. This signal is sent to the ECM. The ECM uses this signal in order to calculate
the engine position and the engine speed.
A loss of the engine speed/timing signal causes the ECM to stop sending power to the
fuel injectors.
Calibration of the timing is required only after the following circumstances:
The ECM has been replaced.
The timing gear and/or the rear gear train have been adjusted.
The timing gear and/or the rear gear train have been replaced.
Test Step 1. Check for an "ACTIVE" Diagnostic Code
A. Remove electrical power to the ECM.
B. Connect Caterpillar Electronic Technician (ET) to the service tool connector.
C. If a timing calibration sensor is not already installed on this application, install
a timing calibration probe onto the engine:
a. Remove the timing calibration plug from the flywheel housing.
b. Examine the flywheel through the timing calibration hole. Ensure that
the probe is not inserted into the timing pin hole. If necessary, rotate
the engine.