Ram Check Error - Bosch ETT 008.31 Repair Instructions

8.4

RAM check error

System parameters are stored in the RAM module. During the RAM check, these system parameters are monitored to ensure that they
remain within sensible limits pre-defined by the manufacturer. If the RAM contents are outside these limits, an error message results.
A faulty RAM content may have various causes:
- A faulty powwer supply (battery)
- Replaced motherboard
- Battery replaced with the exhaust gas analyzer switched off
- Defective RAM module (IC)
- External interference signals due to inadequately shielded peripheral equipment. The connections of the temperature sensor, clamp-
on speed sensor and serial interface must be equipped with perfect shield bonding.
Check that connections comply with circuit diagram in Section 12.
The test function (see Section 4.2) allows you to determine which parameters the exhaust-gas analyzer has recognized as faulty.
Determine and correct the faulty parameters.
Press "Test u" button 7 x :
i The code numbers may appear individually or as the sum total of individual code numbers. In this way, several faulty parameters
can be displayed in a single number, e.g.: 1105 = 1 + 16 + 64 + 1024.
HC display Faulty parameters
1 HC measuring channel mean value,
small measuring range
2 HC measuring channel mean value,
large measuring range
4 HC measuring channel upper range value,
small measuring range
8 HC measuring channel upper range value,
large measuring range
16 CO measuring channel mean value,
small measuring range
32 CO measuring channel mean value,
large measuring range
64 CO measuring channel upper range value,
small measuring range
128 CO measuring channel upper range value,
large measuring range
256 CO measuring channel, mean value
2
512 CO measuring channel, upper range value
2
1024 HC temperature coefficient
2048 CO temperature coefficient
O display Faulty parameters
2
1 Setpoint of HC calibration
2 HC calibration factor
4 Setpoint of CO calibration
8 CO calibration factor
16 Setpoint of CO
32 CO calibration factor
2
64 Unoccupied
128 Unoccupied
256 CO Temperature coefficient
2
512 Altitude
1024 Pump delivery range
2048 Unoccupied
Code numbers which define the faulty parameter(s) appear in the HC and O2 display fields.
calibration
2
For correction see Section:
6.3 Fine-tuning the indicating accuracy
4.1.13 Temperature compensation
For correction see Section:
For Switzerland and GB only
4.1.13 Temperature compensation
4.1.7 Entering the altitude
4.1.9 Adjusting the pump capacity
39