Data Displays
When trouble shooting a malfunction, the ECM and BCM data display can be used to compare the problem vehicle, with a vehicle that is functioning properly. The following is a brief summary of each parameter.
BCM DATA DISPLAY CODES
| Code | Circuit Affected | |
|---|---|---|
| BD20 | Commanded Blower Voltage | |
| BD21 | Coolant Temperature | |
| BD22 | Commanded Air Mix Door Position | |
| BD23 | Actual Air Mix Door Position | |
| BD24 | Air Delivery Mode | |
| 0 | Auto-Recirc/Max A/C | |
| 1 | Auto-A/C (Vents) | |
| 2 | Auto-Bi-Level | |
| 3 | Auto-Heater/Def | |
| 4 | Auto-Heater | |
| 5 | Off | |
| 6 | Normal Purge | |
| 7 | Cold ("DEF") Purge | |
| 8 | Defog | |
| 9 | Forced Lower | |
| 10 | Forced Upper | |
| 11 | Forced Bi-Level | |
| BD25 | In-Car Temperature | |
| BD26 | Actual Outside Temperature | |
| BD27 | High Side Temperature | |
| BD28 | Low Side Temperature | |
| BD32 | Sun Load Temperature Sensor | |
| BD40 | Actual Fuel Level | |
| BD41 | Gear Selector Position Sensor | |
| BD42 | Dimming Pot | |
| BD43 | Twilight Delay Pot | |
| BD44 | Twilight Photocell | |
| BD45 | Phone Mode | |
| 0 | No Phone in System | |
| 1 | OFF | |
| 2 | ON | |
| 3 | ON - No Service | |
| 4 | ON - ROAM | |
| 5 | ON - Call in Progress | |
| 6 | ON - Call Received | |
| 7 | System Problem | |
| BD50 | Battery Voltage | |
| BD51 | Generator Field | |
| BD60 | Vehicle Speed | |
| BD61 | Engine Speed | |
| BD70 | Cruise Servo Position | |
| BD71 | Oil Pressure Sensor | |
| BD90 | Option Content No. 1 | |
| BD91 | Option Content No. 2 | |
| BD92 | Option Content No. 3 | |
| BD98 | Ignition Cycle Counter | |
| BD99 | BCM PROM I.D. | |
| CD99 | CRT PROM I.D. Verification | |