Member Since: 27 Jul 2014
Location: Warsaw/Toronto
Posts: 64
P0407 error after EGR replacement - RESOLVED
Ater replacing my B bank EGR,I got the following code:
P0407-21 (25) Exhaust gas recirculation sensor B circuit low - General signal failure - signal amplitude<minimum)
Any ideas, re-check the connections? Clean the intake manifold? Maybe I got a faulty EGR?
Thanks,
J.
Last edited by pinchy on 3rd Mar 2015 2:24 pm. Edited 1 time in total
2nd Mar 2015 3:34 pm
Allan_T
Member Since: 10 Sep 2012
Location: Northampton
Posts: 1034
This should provide some direction
Causes
Potential causes of a P0407 code include: Short to ground in EGR signal or Reference circuits Short to voltage in EGR ground or signal circuits Bad EGR valve Bad PCM wiring issues due to chafing or loose terminals
Possible Solutions
If you have access to a scan tool you can command the EGR valve on. If it responds and the feedback indicates the valve is moving properly then the problem may be intermittent. Sometimes in cold weather, moisture can freeze in the valve causing it to stick. After the vehicle warms up the problem may disappear. Carbon or other debris can lodge in a valve causing it to stick also If the EGR valve doesn't respond to your commands with the scan tool, disconnect the EGR harness connector. Turn the key to on position, engine off (KOEO). Using a voltmeter, check for 5 volts on the reference wire to the EGR valve. If there is no 5 volts, is there any voltage at all? If there is 12 volts, then repair short to voltage in the 5 volt reference circuit. If there is no voltage connect a test light to battery voltage and probe the 5 volt reference wire. If the test light illuminates, the 5 volt reference circuit is shorted to ground. Repair as necessary. If the test light doesn't illuminate check for an open in the 5 volt reference circuit. Repair as necessary If there is no apparent problem and there is no 5 volt reference, PCM may be at fault, however other codes will likely be present. If 5 volts are present on the reference circuit, jumper the 5 volts to the EGR signal circuit. Now the EGR position on the scan tool should read 100 percent. If it doesn't connect test light to battery voltage and probe the EGR signal circuit. If it illuminates, then the signal circuit is shorted to ground. Repair as necessary. If the light doesn't illuminate, check for an open on the EGR signal circuit. Repair as necessary. If, after jumpering the 5 volt reference circuit to the EGR signal circuit the scan tool EGR position reads 100 percent, then check for poor terminal tension at the EGR valve connector. If the wiring is okay, replace the EGR valve.
Are you sure you changed the right one?. It has been known that some D3's have a wiring fualt to some of the egr connectors, have you checked the wires for damage, also check the main engine ECU for water damage as this is known issue as well.
Flack
2nd Mar 2015 4:01 pm
pinchy
Member Since: 27 Jul 2014
Location: Warsaw/Toronto
Posts: 64
I'm sure about the correct EGR being replaced (see link below). I'm going to re-check all the connections, maybe they were not seated properly. I have a feeling it could be something down the path from the EGR that's causing this...
Just out of curiostiy has anyone ever gotten a faulty EGR? I'm sure it's a matter of time, but I never had this happen before.
@Allan - Thanks! I found that description as well. This error does not come up a lot on the "internets" but the description with all the detailsis nice to have for the future
Member Since: 27 Jul 2014
Location: Warsaw/Toronto
Posts: 64
RESOLVED
Cause: User error
Description: unplugged sensor in intake manifold
How identified:
1) plugged in old EGR - same error - removed new EGR as source of problem
2) Did assessment up the value chain from the EGR to recheck for connections and leaks.
3) Found unplugged sensor
Lessons learned: 1) IID Tool was not reporting stats for one of the sensors. Should have picked-up on this.
3rd Mar 2015 2:23 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Allan_T wrote:
If there is no voltage connect a test light to battery voltage and probe the 5 volt reference wire. If the test light illuminates, the 5 volt reference circuit is shorted to ground. Repair as necessary.
Well I guess the test is valid way of proving a short to ground (!) but not sure every ECU will enjoy 12v down the 5v ref line! There is not even a caution about the current draw of different test lights either (small incandescent, large incandescent or LED type).
There are safer ways of checking for a short to ground on computer circuits, like a quick continuity check.
Anyway, good to hear the issue is sorted and you are not the first either!
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 10 Sep 2012
Location: Northampton
Posts: 1034
pinchy wrote:
RESOLVED
Cause: User error
Description: unplugged sensor in intake manifold
It's easily done and a simple fix in the end. GAP IID Pro Multi Vehicle Defender L316 2007-2015 - Discovery 3 - Discovery 4 - Discovery Sport L550 - Freelander 2 - Range Rover Evoque L538 - Range Rover L322 - Range Rover L405 - Range Rover Sport L320 - Range Rover Sport L494 Electrical Fault Diagnostics
3rd Mar 2015 3:00 pm
Allan_T
Member Since: 10 Sep 2012
Location: Northampton
Posts: 1034
Robbie wrote:
Allan_T wrote:
If there is no voltage connect a test light to battery voltage and probe the 5 volt reference wire. If the test light illuminates, the 5 volt reference circuit is shorted to ground. Repair as necessary.
Well I guess the test is valid way of proving a short to ground (!) but not sure every ECU will enjoy 12v down the 5v ref line! There is not even a caution about the current draw of different test lights either (small incandescent, large incandescent or LED type).
There are safer ways of checking for a short to ground on computer circuits, like a quick continuity check
The safest option would be to disconnect the ECU before conducting the short to ground test with the test light. At the end of the day these tests are not for the uninitiated and most tend to steer clear of electronics GAP IID Pro Multi Vehicle Defender L316 2007-2015 - Discovery 3 - Discovery 4 - Discovery Sport L550 - Freelander 2 - Range Rover Evoque L538 - Range Rover L322 - Range Rover L405 - Range Rover Sport L320 - Range Rover Sport L494 Electrical Fault Diagnostics
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