For 1990-2009 cars

### Diagnostic Aids

Perform the following in order to avoid a misdiagnosis:

• | Ensure that the following cruise control switches are not stuck in the engaged position:

• | On/off switch

• | Set/coast switch

• | Resume/accel switch

• | Inspect for proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation .

• | Inspect for proper adjustment of the TCC brake/cruise release switch. Refer to Cruise Release Switch Adjustment .

• | Inspect for proper adjustment of the clutch release switch. Refer to Clutch Pedal Cruise Control Release Switch Adjustment .

• | Inspect for proper operation of the clutch pedal.

• | For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Cruise Control Schematics Connector End View Reference: Master Electrical Component List
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Turn the cruise control On/Off switch Off.
4. With the scan tool, observe the following cruise control parameters in the Cruise Control Data list:

• | Cruise On/Off Switch

• | Cruise Resume/Accel Switch

• | Cruise Set/Coast Switch

Do all of the parameters listed above display Off?

--

Go to Step 3

Go to Step 13

3 |

1. With the scan tool, observe the Cruise On/Off Switch parameter.
2. Turn the cruise On/Off switch ON.

Does the Cruise On/Off Switch parameter display On?

--

Go to Step 4

Go to Step 11

4 |

1. With the scan tool, observe the Cruise Set/Coast Switch parameter.
2. Press and hold the set/coast switch.

Does the Cruise Set/Coast Switch parameter display On?

--

Go to Step 5

Go to Step 12

5 |

1. With the scan tool, observe the Cruise Resume/Accel Switch parameter.
2. Press and hold the resume/accel switch.

Does the Cruise Resume/Accel Switch parameter display On?

--

Go to Step 6

Go to Step 12

6 | Do the stop lamps operate properly? | -- | Go to Step 7 | Go to Stop Lamps Inoperative or Go to Stop Lamps Always On
7 | Test the stop lamp supply voltage circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 8
8 | Is the vehicle equipped with a manual transmission? | -- | Go to Step 9 | Go to Step 20
9 |

1. Turn OFF the ignition.
2. Disconnect the clutch release switch.
3. With a DMM, measure the resistance of the clutch pedal position (CPP) switch between the ignition 1 voltage circuit and the CPP switch signal circuit.

Does the resistance measure between the specified values?

10-15 Ω

Go to Step 10

Go to Step 18

10 |

1. Depress and hold down the clutch pedal.
2. With a DMM, measure the resistance of the CPP switch between the ignition 1 voltage circuit and the CPP switch signal circuit.

Does the resistance measure at the specified value?

O.L.

Go to Step 14

Go to Step 18

11 | Connect a DMM between the ignition 1 voltage circuit at the back of C200 and a good ground. Does the voltage measure at the specified value? | B+ | Go to Step 12 | Go to Step 21
12 | Important: The cruise control On/Off switch must be turned ON in order to correctly view the set/coast resistance value with the DMM.

1. Turn OFF the ignition.
2. Disconnect C200.
3. With a DMM, measure the resistance of the cruise control switch between the ignition 1 voltage circuit and the cruise control set/coast and resume/accelerate switch signal circuit.
4. Individually activate and hold the cruise control function switches while measuring the resistance of the cruise control function switches.

Do the cruise control function switch resistance values measure between the specified values?

Off = O.L.

On = 7.8 K Ω - 8.6 K Ω

Resume = 2.7 K Ω - 3.0 K Ω

Set = 1.2 K Ω - 1.3 K Ω

Go to Step 17

Go to Step 19

13 | Important: The cruise control On/Off switch must be turned ON in order to correctly view the set coast resistance value with the DMM.

1. Turn OFF the ignition.
2. Disconnect C200.
3. With a DMM, measure the resistance of the cruise control switch between the ignition 1 voltage circuit and the cruise control set/coast and resume/accelerate switch signal circuit.
4. Individually activate and hold the cruise control function switches while measuring the resistance of the cruise control function switches.

Do the resistance values measure at the specified values?

Off = O.L.

On = 7.8 K Ω - 8.6 K Ω

Resume = 2.7 K Ω - 3.0 K Ω

Set = 1.2 K Ω - 1.3 K Ω

Go to Step 16

Go to Step 19

14 |

1. Turn ON the ignition, with the engine OFF.
2. Connect a test lamp between the ignition 1 voltage circuit and a good ground.

Does the test lamp illuminate?

--

Go to Step 15

Go to Step 21

15 | Test the clutch switch signal circuit for the following:

• | An open

• | A short to voltage

• | A short to ground

• | A high resistance

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 20

16 | Test the cruise control set/coast and resume/accelerate switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 20
17 | Test the cruise control set/coast and resume/accelerate switch signal circuit for the following:

• | An open

• | A high resistance

• | A short to ground

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 20

18 | Inspect for poor connections at the harness connector of the clutch switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 22
19 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 23
20 | Inspect for poor connections at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 24
21 | Repair the following in the ignition 1 voltage circuit:

• | An open

• | A high resistance

• | A short to ground

Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 25

--

22 | Replace the clutch release switch. Refer to Clutch Pedal Cruise Control Release Switch Replacement . Did you complete the replacement? | -- | Go to Step 25 | --
23 | Replace the cruise control switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the replacement? | -- | Go to Step 25 | --
24 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 25 | --
25 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate properly? | -- | System OK | Go to Step 2