Default Modes
Possible TCM default
- Fixed 4th gear
- Erratic gear shifts
Possible ECM default
- Throttle motor and relay disabled
- Throttle valve opening set to default value
- Idle speed controlled by fuel injection intervention
- Idle speed adaptation inhibited
- Throttle opening limited to 30%
- Vehicle speed limited
- Speed (cruise) control limited
- Maximum throttle opening for N range inhibited
- Maximum engine speed reduced
- HO2 sensor control circuit inhibited
- Maximum ignition retard
Pinpoint tests
| CAUTION | Diagnosis by substitution from a donor vehicle is NOT acceptable. Each vehicle is configured to it's own vehicle identification data (VID) block, and substitution of control modules may not only not confirm a fault, but may cause faults in the vehicle being tested and/or the donor vehicle. Failure to follow this instruction may result in damage to the vehicle. |
| CAUTION | Electronic modules are sensitive to static electrical charges. If exposed to these charges, damage may result. Failure to follow this instruction may result in damage to the vehicle. |
| CAUTION | When probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit, part number 3548-1358-00. Failure to follow this instruction may result in damage to the vehicle. |
Note. When performing voltage or resistance tests, always use a digital multimeter (DMM) accurate to 3 decimal places, and with an up-to-date calibration certificate. When testing resistance, always take the resistance of the DMM leads into account.
Note. Before beginning any diagnosis of the D2B system, codes B1342, U2602, or U2603 must be rectified. No D2B function is possible with these failures present.
Note. Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
Note. If DTCs are recorded and the symptom is not present when performing the pinpoint tests, an intermittent concern may be the cause. Always check for loose connections and corroded terminals.