Functional Check P72
Malfunctions can be either mechanical or electrical. In resolving any cruise control system problem, complete the preliminary inspection first.
Preliminary Inspection
| • | Check the fuse(s). |
| • | Check for bare, broken or disconnected wires. |
| • | Check for dirty, corroded or loose ground terminals. |
| • | Check for a binding or sticking linkage at the throttle body. |
| • | Check for damaged or misadjusted release switches. |
Use this procedure to check the operating modes of the cruise control system. This procedure should always be used after repair work has been completed on the cruise control system.
- Slide the cruise control switch to the ON position.
- Check the low speed inhibit by driving the vehicle at a speed of 32 km/h (20 mph). Depress the SET button and release it. Cruise control should not engage.
- Check the set speed by driving the vehicle at a steady speed of 89 km/h (55 mph). Depress the SET button completely and release it. Cruise control should engage at approximately 89 km/h (55 mph).
- Check the brake release by depressing the brake pedal. The cruise control must release the throttle, allowing the vehicle speed to drop. The system must not re-engage when the brake is released.
- Check the resume feature as follows: With the vehicle speed at approximately 72 km/h (45 mph), slide the cruise control switch momentarily (less than 1 second) to the R/A position. The vehicle should accelerate to approximately 89 km/h (55 mph).
- Check the coast feature by depressing the SET button and holding it. Allow the vehicle speed to drop to 80 km/h (50 mph) and release the button. Cruise control should hold the vehicle speed at approximately 80 km/h (50 mph).
- Check the accelerate feature by sliding the cruise control switch to the R/A position and holding it. The vehicle speed should begin to increase. Allow the speed to increase to 89 km/h (55 mph) and release the switch. The cruise control should hold the vehicle at approximately 89 km/h (55 mph).
- Check the OFF switch by turning the cruise control switch to the OFF position. This must disengage the cruise control system.
If the preliminary inspections reveal no solutions, refer to the Driveability, Emissions and Electrical Diagnosis manual for this model.
Functional Check P92
Lamp Usage | Quantity | Trade No. |
|---|---|---|
Anti-Lock Brake System Warning Indicator Lamp (P92) | 1 | 194 |
Daytime Running Lights Indicator Lamp (P72) | 1 | PC118 |
Directional Signal Indicator Lamp (P72) | 2 | PC194 |
Directional Signal Indicator Lamp (P92) | 2 | 194 |
Do Not Shift Warning Light (P92) | 1 | 194 |
Door Ajar Indicator Lamp (P72) | 1 | PC74 |
Fasten Safety Belts Indicator Lamp (P72) | 1 | PC74 |
Glow Plugs Indicator Lamp (P72) | 1 | PC74 |
Headlamp High Beam Indicator Lamp (P72) | 1 | PC74 |
Headlamp High Beam Indicator Lamp (P92) | 1 | 194 |
Instrument Cluster Illumination Lamp (P72) | 6 | 194 |
Instrument Cluster Illumination Lamp (P92) | 5 | 802 |
Low Air Pressure Warning Indicator Lamp (P92) | 2 | 194 |
Low Coolant Indicator Lamp (P72) | 1 | PC74 |
Low Coolant Indicator Lamp (P92) | 1 | 194 |
Malfunction Indicator Lamp (P72) | 1 | PC74 |
Park Brake Warning Indicator Lamp (P72) | 1 | PC74 |
Park Brake Warning Indicator Lamp (P92) | 1 | 194 |
Service Brake Warning Indicator Lamp (P72) | 1 | PC74 |
Service Brake Warning Indicator Lamp (P92) | 1 | 194 |
Speedometer Illumination Lamp (P92) | 2 | 812 |
Tachometer Illumination Lamp (P92) | 1 | 812 |
Transmission Control Illumination Lamp (P72) | 1 | 73 |
Transmission Indicator Lamp (P72) | 1 | PC74 |
Transmission Temperature Warning Indicator Lamp (P92) | 1 | 194 |
Water In Fuel Indicator Lamp (P72) | 1 | PC74 |
Functional Check P72 Off Test
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Is the action complete? | -- | Go to Step 2 | -- |
2 | With the Allison AT 542 transmission option, measure the resistance between pins 1 and 25 of the ECU. Is the resistance within the specified values? | 80-500 ohms | Go to Step 4 | Go to Step 3 |
3 | Repair the wire or the sender unit. Is the repair complete? | -- | System OK | -- |
4 | Measure the resistance between pins 14 and 18 of the ECU (the cruise ON bulb). Is the resistance within the specified values? | 20-24 ohms | Go to Step 6 | Go to Step 5 |
5 | Repair the wiring or replace the bulb. Is the repair complete? | -- | System OK | -- |
6 | Measure the resistance between pins 20 and 21 of the ECU (the actuator motor). Is the resistance within the specified values? | 2-8 ohms | Go to Step 7 | Go to Step 8 |
7 |
Does the meter read continuity first and infinity when the leads are reversed? | -- | Go to Step 12 | Go to Step 11 |
8 | Check the resistance at actuator pins D and C. Is the resistance within the values specified? | 2-8 ohms | Go to Step 9 | Go to Step 10 |
9 | Check and repair any faulty wiring. Is the repair complete? | -- | System OK | -- |
10 | Replace the actuator. Is the repair complete? | -- | System OK | -- |
11 | Perform another diode check with the positive lead on pin A and the negative lead on pin B, the reverse the leads. Does the meter read continuity first and infinity when the leads are reversed? | -- | Go to Step 9 | Go to Step 10 |
12 | Check for continuity between pins 14 and 15 with the memory switch in the SET/ACCEL position. Is there continuity? | -- | Go to Step 14 | Go to Step 13 |
13 | Check and repair any faulty wiring, especially the wire connectors at the 6-way connector or replace the switch. Is the repair complete? | -- | System OK | -- |
14 | Check for continuity between pins 14 and 16 with the memory switch in the CANCEL/RESUME position. Is there continuity? | -- | Go to Step 15 | Go to Step 13 |
15 | Check resistance between pins 25 and 20, 21, 22 and 23 in turn. Is resistance infinite? | -- | Go to System "ON" Tests | Go to Step 16 |
16 | Check for infinite resistance between the actuator case and the actuator wires. Is the resistance infinite? | -- | Go to Step 9 | Go to Step 10 |
Functional Check P92 Off Test
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Are 12V present? | -- | Go to Step 2 | Go to Step 3 |
2 | Check the brake supply at ECU pins 7 and 25. Are 12V present? | -- | Go to Step 4 | Go to Step 5 |
3 | Check the wiring to and through the power ON switch and repair as necessary. Is the repair complete? | -- | System OK | -- |
4 | Check the brake lamps at ECU pins 8 and 25. Is less than 1V present? | -- | Go to Step 6 | Go to Step 7 |
5 | Check the wiring to the hot side of the brake switch and repair as necessary. Is the repair complete? | -- | System OK | -- |
6 | Check the brake lamps with the brakes applied at ECU pins 8 and 25. Are more than 6V present? | -- | Go to Step 8 | Go to Step 9 |
7 |
Is the repair complete? | -- | System OK | -- |
8 | Raise the drive wheels or test drive the vehicle and check the speed signal at ECU pins 1 and 25. Are more than 0.7V present? | -- | Go to RV2 Adjustment | Go to Step 10 |
9 | Check the wiring and the brake switch and repair as necessary. Is the repair complete? | -- | System OK | -- |
10 | Check the wiring and the speed signal source and repair as necessary. Is the repair complete? | -- | System OK | -- |
