Reading and Clearing Diagnostic Trouble Codes
How to Troubleshoot the Adaptive Cruise Control (ACC)
Adaptive Cruise Control (ACC) Indicator (Amber)
When the ACC system is OK, the ACC indicator comes on for about 2 seconds after turning the ignition switch to ON (II), then it goes off.
When the ACC system detects a problem while in operation, the ACC system stops control, and the ACC indicator changes from green to amber and stays on.
NOTE: The ACC system is communicating with the PCM, the VSA system, and the gauge control module by F-CAN. If a connected unit malfunctions, the ACC system does not operate. In this case, both the ACC indicator and the connected unit indicator come on and stay on (except the gauge control module).
Adaptive Cruise Control (ACC) Indicator (Green)
If the ACC system is normal, the indicator comes on when the ACC switch is ON, and goes off when the ACC switch is OFF. If the ACC system malfunctions, the indicator color changes from green to amber, and stays on.
Self-diagnostic Function
The ACC system has a self-diagnostic function. If the self-diagnostic function detects a malfunction, the ACC system stops control, turns on the ACC indicator (Amber), and stores DTCs.
Multi-information Display (MID) Indication
If the ACC system is normal, the ACC indicates its operation on the multi-information display (MID) when the ACC switch is ON.
ACC Unit
The ACC unit uses input from the millimeter wave radar to control the vehicle's speed and brakes to maintain a constant distance between the vehicle and other moving vehicles directly ahead.
Millimeter Wave Radar
The millimeter wave radar recognizes the position of the moving vehicle ahead and detects the two vehicles speed differential.
The ACC unit receives this information from the millimeter wave radar.
The millimeter wave radar also detects its own errors, and it signals the ACC unit if an error is detected.
CAN Communication
The ACC unit is on the F-CAN, and it communicates with other units (AcuraLink, gauge control module, navigation, steering angle sensor, PCM, SH-AWD, SRS, and VSA) via the F-CAN.
If the ACC unit detects a communication error or a malfunction in another connected unit, the ACC system will not operate even though it is OK.
In this case, both the ACC indicator and the related unit indicator will come on and stay on.
Millimeter Wave Radar Aiming
If the millimeter wave radar is removed or replaced, do the millimeter wave radar aiming procedure. If the aiming is incomplete, the ACC indicator comes on.
How to Troubleshoot DTCs
Check the DTCs with the HDS. Make a copy of the freeze data, then clear the DTC.
Before troubleshooting, check and note these items:
- Ask the client about the conditions when the problem occurred, and try to reproduce the same conditions for troubleshooting.
- If the symptom does not appear and the ACC indicator does not come on during the test-drive, but troubleshooting is done based on the DTC, check for poor connections or loose terminals at all connectors related to the circuit that you are troubleshooting.
- After the troubleshooting or repairs are done, clear the DTCs, and test-drive the vehicle under the same conditions as when the DTC was originally set. Make sure the ACC indicator does not come on.
- The ACC system sometimes stops control because of the environment (weather, road conditions, driving conditions, etc.). A DTC may be stored in these cases.
DTCs may be stored even when the system is normal:
ACC indicator does not go on
DTC 83: Millimeter Wave Radar Detection Unstable
Driving behind a target vehicle that caused unstable reception.
DTC 84: Target vehicle comes closer than the millimeter wave radar detecting limits
The target vehicle brakes suddenly, etc.
DTC 85: Extensive driving on a rough or winding road, or VSA system malfunction
DTC 86: Abnormal tire pressure
Abnormal tire pressure, flat tire.
DTC 87: Adaptive cruise control (ACC) brake control temporarily prohibited
ACC brake works continuously, or ACC brake control is temporarily prohibited by a communication line error detected between the ACC unit and VSA modulator-control unit.
DTC 88: Millimeter wave radar out of detection area
Millimeter wave radar temperature is too high, millimeter wave radar supply voltage is too low, or out of detection condition.
DTC 89: Front wheel spin
DTC 91: Vehicle skidded, spun out, or abrupt steering wheel movements
DTC 93: Front tire problem
Different diameter of tires, flat tire, or large air pressure differential.
DTC 94: Rear tire problem
Different diameter of tires, flat tire, or large air pressure differential.
DTC 95: Power supply voltage too high
DTC 96: Power supply voltage too low
DTC 99: Acceleration/deceleration abnormality
Detects acceleration or deceleration that is out of the normal system operating range.
DTC 101: Rear wheel locked
Driving with the parking brake applied, or the parking brake stuck.
How to Retrieve DTCs
1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) (A) under the left side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the ACC unit. If it does not communicate, troubleshoot the DLC circuit. Testing and Inspection
4. Follow the prompts on the HDS to display the DTC(s) on the screen. After determining the DTC, refer to the DTC Troubleshooting.
NOTE:
- See the HDS Help menu for specific instructions.
- Before troubleshooting, always verify that you have the latest version of the HDS software.
How to Clear DTCs
NOTE: You cannot clear the DTCs manually.
1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) (A) under the left side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the ACC unit. If it does not communicate, troubleshoot the DLC circuit. Testing and Inspection
4. Clear the DTC(s) by following the screen prompts on the HDS.
NOTE: See the HDS Help menu for specific instructions.
