Atlas Copco QAS246 Gd USA troubleshooting: 31 fault codes and 25 symptom-cause-remedy entries from the manufacturer's own service documentation.
Atlas Copco QAS246 Gd USA — full specs, parts & maintenance.
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 11 | VSG input low | ||
| 12 | VSG input high | ||
| 13 | Coolant level circuit low | ||
| 14 | Intercooler, coolant or oil temperature circuit high | ||
| 15 | Intercooler, coolant or oil temperature circuit low | ||
| 16 | Coolant level circuit high | ||
| 17 | Bypass position circuit high | ||
| 18 | Bypass position circuit low | ||
| 21 | TPS circuit high | ||
| 22 | TPS circuit low | ||
| 23 | Fuel temperature circuit high | ||
| 24 | Fuel temperature circuit low | ||
| 46 | Battery voltage low | ||
| 47 | Fuel pressure high | ||
| 48 | Fuel pressure low | ||
| 52 | A/D conversion fail | ||
| 53 | EEPROM write or nonvolatile checksum fail | ||
| 54 | Vehicle speed sensor fault | ||
| 55 | J1939 data link fault | ||
| 56 | J1587 data link fault | ||
| 57 | J1922 data link fault | ||
| 58 | Torque overload | ||
| 61 | Injector response time long | ||
| 62 | Auxiliary output open or short to | ||
| Blown fuse | Alternator does not excite. | Replace fuse. | |
| Increase the speed by 15 % | Insufficient residual voltage. | ||
| Reset voltage | Low voltage at no load. | Voltage potentiometer out of setting. | |
| Check rpm | Intervention of protection. | Winding failure. | Check windings. |
| Substitute regulator. | High voltage at no load. | Voltage potentiometer out of setting. | |
| Reset voltage potentiometer. | Lower than rated voltage at load. | ||
| Substitute regulator. | Current too high, power factor lower than 0.8; speed lower than 10 % of rated speed. |
| Symptom | Cause | Remedy |
|---|---|---|
| Alternator does not excite | Blown fuse | Replace fuse |
| Alternator does not excite | Insufficient residual voltage | Increase the speed by 15 % |
| Alternator does not excite | No residual voltage | For an instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities |
| After being excited alternator does not excite | Connections are interrupted | Check connection cables as per attached drawings |
| Low voltage at no load | Voltage potentiometer out of setting | Reset voltage |
| Low voltage at no load | Intervention of protection | Check rpm |
| Low voltage at no load | Winding failure | Check windings |
| High voltage at no load | Voltage potentiometer out of setting | Reset voltage |
| High voltage at no load | Failed regulator | Substitute regulator |
| Lower than rated voltage at load | Voltage potentiometer out of setting | Reset voltage potentiometer |
| Lower than rated voltage at load | Intervention by protection | Current too high, power factor lower than 0.8; speed lower than 10 % of rated speed |
| Lower than rated voltage at load | Failed regulator | Substitute regulator |
| Lower than rated voltage at load | Rotating bridge failure | Check diodes, disconnect cables |
| Higher than rated voltage at load | Voltage potentiometer out of setting | Reset voltage potentiometer |
| Higher than rated voltage at load | Loose sensing wires on AVR | Check sensing wires on AVR |
| Higher than rated voltage at load | Failed regulator | Substitute regulator |
| Unstable voltage | Speed variation in engine | Check regularity of rotation |
| Unstable voltage | Regulator out of setting | Regulate stability of regulator by acting on “STABILITY” potentiometer |
| Engine runs in idle speed | No SAPE connected | Put single/parallel switch in single position |
| No residual voltage. | ||
| After being excited alternator does not excite. | Connections are interrupted. | |
| Failed regulator. | Rotating bridge failure. | |
| Higher than rated voltage at load. | ||
| Unstable voltage. | Speed variation in engine. | |
| Engine runs in idle speed. | No SAPE connected. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Voltage potentiometer out of setting; Intervention of protection; Winding failure; Voltage potentiometer out of setting.. See the table for the matching fixes.
Documented causes: Voltage potentiometer out of setting; Intervention by protection; Failed regulator; Rotating bridge failure. See the table for the matching fixes.
Documented causes: Blown fuse; Insufficient residual voltage; No residual voltage. See the table for the matching fixes.