DTC 5-3-3
5-3-3 POWER STAGE GROUP CPreconditions for DTC
^ If the ECM registers a fault in the circuits for the Fan Control (FC) relay, EGR controller, RPM signal to the combined instrument, load signal for the AW 50-42 transmission, Engine Coolant Temperature (ECT) signal to the combined instrument or fuel consumption signal to the trip computer, but cannot determine which circuit is faulty, DTC 5-3-3- is set.
Substitute values
^ Idle air trim is inhibited.
^ Fuel trim is inhibited.
^ Conditions for fuel shut-off changed.
Fault sources
^ Signal lead engine cooling fan (FC) full speed short circuited to voltage supply.
^ Defective FC relay.
^ Signal lead, EGR controller short circuited to voltage supply.
^ Defective EGR controller.
^ Signal lead RPM (to combined instrument) short circuited to voltage supply.
^ Signal lead load (to transmission) short circuited to voltage supply.
^ Signal lead ECT (to combined instrument) short circuited to voltage supply.
^ Signal lead fuel consumption signal to trip computer short circuited to voltage supply.
Fault symptoms
^ Depending on fault source; no RPM reading on tachometer, no ECT reading on combined instrument, indicator for automatic transmission lights up and unrealistic fuel consumption figures from the trip computer.
TESTING PROCEDURE
Checking the Signal Lead, Engine Cooling Fan Full Speed
^ Switch Ignition OFF.
^ Disconnect connector B from the FC relay.
^ Switch Ignition ON.
^ Connect a voltmeter between FC relay coupling B connector 2 (for ECM) and ground.
The voltmeter should show 0 - 1 Volt.
If the reading is OK:
- Check the FC fan relay.
If the reading is incorrect:
- Check the lead between the FC relay connector B2 and ECM A22 for signs of short circuiting to voltage supply.
Checking the Fan Control (FC) Relay
^ Switch Ignition OFF.
^ Connector B disconnected.
^ Disconnect connector A from the FC relay.
^ Connect an ohmmeter between connectors A1 and B2 on the FC relay.
The ohmmeter should show approx. 80 ohms at +20°C (68°F).
If the reading is OK:
- On cars equipped with EGR:
Check the signal lead for the EGR controller.
- On cars not equipped with EGR:
Check the RPM signal lead.
If the reading is incorrect:
- Test with a new FC relay.
Checking the Signal Lead, EGR Controller
^ Switch Ignition OFF.
^ Disconnect the EGR controller.
^ Switch Ignition ON.
^ Connect a voltmeter between the EGR controller's connector 2 and ground.
The voltmeter should show 0 - 1 Volts.
If the reading is OK:
- Check the EGR controller.
If the reading is incorrect:
- Check the lead between the EGR controller connector 2 and ECM A40 for signs of short circuiting to voltage supply.
Checking the EGR Controller
^ Switch Ignition OFF.
^ EGR controller disconnected.
^ Connect an ohmmeter between the EGR controller's connectors 1 and 2.
The ohmmeter should show 75 - 95 ohms, at +20°C (68°F).
If the reading is OK:
- Check the RPM signal lead.
If the reading is incorrect:
- Test with a new EGR controller.
Checking the Signal Lead For RPM Reading
^ START the engine and let it run at idling speed.
^ Connect a voltmeter between connectors #21 (ECM B21) and #28 (ECM B28) on the break-out box.
The voltmeter should show 6 - 7 Volts.
If the reading is OK:
- Cars equipped with automatic transmission:
Check the load signal lead.
- Cars not equipped with automatic transmission:
Check the temperature signal lead as per EBO7
If the reading is incorrect:
- Check the lead between combined instrument panel A11 and ECM B21 for signs of short circuiting to voltage supply.
Checking the Signal Lead Load
^ Connect the break-out box and check the ground connectors.
^ Connect the ECM.
^ Switch Ignition ON.
^ Connect a voltmeter between connectors #12 (ECM B12) and #28 (ECM B28) on the break-out box.
The voltmeter should show 0 - 1 Volt.
If the reading is OK:
- Check the temperature signal lead.
If the reading is incorrect:
- Check the lead between ECM B12 and TCM B12 for signs of short circuiting to voltage supply.
Checking the Signal Lead for Temperature
^ Switch Ignition ON.
^ Connect a voltmeter between connectors #23 (ECM B23) and #28 (ECM B28) on the break-out box.
The voltmeter should show 4 - 8 Volts.
If the reading is OK:
- Cars equipped with a trip computer:
Check the trip computer signal lead.
- Cars not equipped with a trip computer:
The fault is intermittent. Proceed to: INTERMITTENT FAULT section below.
If the reading is incorrect:
- Check the lead between combined instrument panel #A26 and ECM B23 for signs of short circuiting to voltage supply.
- On cars with ECC check also the lead between ECM B23 and ECC control module #A23 for signs of short circuiting to voltage supply.
Checking the Signal Lead for the Trip Computer
^ Switch Ignition ON.
^ Connect a voltmeter between connectors #39 (ECM B39) and #28 (ECM B28) on the break-out box.
The voltmeter should show 0 - 1 Volt.
If the reading is OK:
- The fault is intermittent. Proceed to INTERMITTENT FAULT section below.
If the reading is incorrect:
- Check the lead between combined instrument panel A9 and ECM B39 for signs of short circuiting to voltage supply.
INTERMITTENT FAULT
Checking the Leads and Connections
^ Check the lead between the FC relay connector B2 and ECM A22 for signs of intermittent short circuiting to voltage supply.
^ Check the lead between EGR controller connector 2 and ECM A40 for signs of intermittent short circuiting to voltage supply.
^ Check the lead between combined instrument panel A11 and ECM B21 for signs of intermittent short circuiting to voltage supply.
^ Check the lead between Motronic Control Module (ECM) B12 and TCM B12 for signs of intermittent short circuiting to voltage supply.
^ Check the lead between combined instrument panel A26 and ECM B23 for signs of intermittent short circuiting to voltage supply.
On cars with ECC, check also the lead between ECM B23 and ECC control module A23 for signs of intermittent short circuiting to voltage supply.
^ Check the lead between combined instrument panel A9 and ECM B39 for signs of intermittent short circuiting to voltage supply.