Cruise Control Z17DTL AstraG

Astra G Cruise control for 1.7 CDTI models

(verified on engine code Z17DTL – ECO4 model)

These cars have the ‘fly by wire’ electronic throttle control so adding Cruise Control is easy.  The basic upgrade is a stalk (about £30), a few wires and a different brake pedal switch.  The clutch switch is already fitted to all diesels, but the wiring to the stalk is not, so will need to be added.

Overall procedure:

  1. Access engine ECU (inside left-front wing, above arch liner).
  2. Check ECU for wires at pins  53, 56 and 57.
  3. If wires are not present at the ECU, add them (hint: you can get spare terminals from a scrap yard by cutting off the ECU loom connector).
  4. Once you have the wires at the ECU, extend them into the car and up to the steering column.
  5. Connect the new wires from the ECU to the stalk and clip into place instead of your existing indicator stalk (see below for details).
  6. Secure wiring and refit the column covers.
  7. Remove noise insulation cover from pedal area, remove brake switch and replace with the dual one.  Note that it’s possible to use switches from other models by cutting the central orientation plug and rotating the connector through 90 degrees before plugging in.
  8. Using Tech2 (OPCOM may also work), select Diagnostics> Engine> Programming> Variant coding, enter security code and select Cruise Control to be ‘Present’.  Click ‘Program’ and you’re done.
  9. Using Tech2, check the Data List in the Engine ECU for correct operation of all components. (I,R,C stalk switches, brake1, brake2 and clutch).
  10. Go for a drive – Cruise control is set using the ‘I’ button on the stalk.  Once set, the speed can be increased using ‘I’ and reduced using the ‘R’ button.  To exit cruise mode, either click the ‘C’ button, press the brake or clutch pedals.
  11. If something doesn’t work as expected, check carefully that the brake pedal switch is operating correctly – it’s common that a ‘right looking’ switch is wired wrongly, often given away by brake lights being ON until you brake, when they switch OFF.  Rotate the connector to resolve.

I created this thread on AOC when I fitted cruise control to my 2003 Astra ECO4 – it provides a little more information and might answer some questions:


Connections between the engine ECU and Cruise Control stalk:

  • Pin A on CC switch goes to pin 53 on the ECU
  • Pin B on CC switch goes to ignition live
  • Pin C on CC switch goes to pin 56 on the ECU
  • Pin D on CC switch goes to pin 57 on the ECU

The relevant part of the ECU wiring diagram (click to enlarge):

CruiseControl Z17DTL wiring diagram

The ECU wiring connector to check / add wires to (click to enlarge): 

CruiseControl Z17DTL ECU Pinout

Any errors or omissions – please get in touch and I will edit this page.  Feel free to link to it if it’s useful. 🙂